32 results on '"Altman, Dg"'
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2. Reporting of noninferiority and equivalence randomized trials: extension of the CONSORT 2010 statement.
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Piaggio G, Elbourne DR, Pocock SJ, Evans SJ, Altman DG, CONSORT Group, Piaggio, Gilda, Elbourne, Diana R, Pocock, Stuart J, Evans, Stephen J W, and Altman, Douglas G
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BIOLOGICAL assay ,CLINICAL trials ,EXPERIMENTAL design ,QUALITY control ,RESEARCH funding ,STATISTICS ,SAMPLE size (Statistics) ,DATA analysis ,TREATMENT effectiveness - Abstract
The CONSORT (Consolidated Standards of Reporting Trials) Statement, which includes a checklist and a flow diagram, is a guideline developed to help authors improve the reporting of the findings from randomized controlled trials. It was updated most recently in 2010. Its primary focus is on individually randomized trials with 2 parallel groups that assess the possible superiority of one treatment compared with another. The CONSORT Statement has been extended to other trial designs such as cluster randomization, and recommendations for noninferiority and equivalence trials were made in 2006. In this article, we present an updated extension of the CONSORT checklist for reporting noninferiority and equivalence trials, based on the 2010 version of the CONSORT Statement and the 2008 CONSORT Statement for the reporting of abstracts, and provide illustrative examples and explanations for those items that differ from the main 2010 CONSORT checklist. The intent is to improve reporting of noninferiority and equivalence trials, enabling readers to assess the reliability of their results and conclusions. [ABSTRACT FROM AUTHOR]
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- 2012
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3. Reporting of noninferiority and equivalence randomized trials: an extension of the CONSORT statement [corrected] [published erratum appears in JAMA Oct 18;296(15):1842].
- Author
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Piaggio G, Elbourne DR, Altman DG, Pocock SJ, Evans SJW, and CONSORT (Consolidated Standards of Reporting Trials) Group
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- 2006
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4. Constraints on publication rights in industry-initiated clinical trials.
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Gøtzsche PC, Hróbjartsson A, Johansen HK, Haahr MT, Altman DG, and Chan A
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- 2006
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5. Reporting of Multi-Arm Parallel-Group Randomized Trials: Extension of the CONSORT 2010 Statement.
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Juszczak E, Altman DG, Hopewell S, and Schulz K
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- Checklist, Humans, Periodicals as Topic standards, Publishing standards, Randomized Controlled Trials as Topic standards
- Abstract
Importance: The quality of reporting of randomized clinical trials is suboptimal. In an era in which the need for greater research transparency is paramount, inadequate reporting hinders assessment of the reliability and validity of trial findings. The Consolidated Standards of Reporting Trials (CONSORT) 2010 Statement was developed to improve the reporting of randomized clinical trials, but the primary focus was on parallel-group trials with 2 groups. Multi-arm trials that use a parallel-group design (comparing treatments by concurrently randomizing participants to one of the treatment groups, usually with equal probability) but have 3 or more groups are relatively common. The quality of reporting of multi-arm trials varies substantially, making judgments and interpretation difficult. While the majority of the elements of the CONSORT 2010 Statement apply equally to multi-arm trials, some elements need adaptation, and, in some cases, additional issues need to be clarified., Objective: To present an extension to the CONSORT 2010 Statement for reporting multi-arm trials to facilitate the reporting of such trials., Design: A guideline writing group, which included all authors, formed following the CONSORT group meeting in 2014. The authors met in person and by teleconference bimonthly between 2014 and 2018 to develop and revise the checklist and the accompanying text, with additional discussions by email. A draft manuscript was circulated to the wider CONSORT group of 36 individuals, plus 5 other selected individuals known for their specialist knowledge in clinical trials, for review. Extensive feedback was received from 14 individuals and, after detailed consideration of their comments, a final revised version of the extension was prepared., Findings: This CONSORT extension for multi-arm trials expands on 10 items of the CONSORT 2010 checklist and provides examples of good reporting and a rationale for the importance of each extension item. Key recommendations are that multi-arm trials should be identified as such and require clear objectives and hypotheses referring to all of the treatment groups. Primary treatment comparisons should be identified and authors should report the planned and unplanned comparisons resulting from multiple groups completely and transparently. If statistical adjustments for multiplicity are applied, the rationale and method used should be described., Conclusions and Relevance: This extension of the CONSORT 2010 Statement provides specific guidance for the reporting of multi-arm parallel-group randomized clinical trials and should help provide greater transparency and accuracy in the reporting of such trials.
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- 2019
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6. Guidelines for the Content of Statistical Analysis Plans in Clinical Trials.
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Gamble C, Krishan A, Stocken D, Lewis S, Juszczak E, Doré C, Williamson PR, Altman DG, Montgomery A, Lim P, Berlin J, Senn S, Day S, Barbachano Y, and Loder E
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- Delphi Technique, Clinical Trials as Topic standards, Data Interpretation, Statistical, Statistics as Topic standards
- Abstract
Importance: While guidance on statistical principles for clinical trials exists, there is an absence of guidance covering the required content of statistical analysis plans (SAPs) to support transparency and reproducibility., Objective: To develop recommendations for a minimum set of items that should be addressed in SAPs for clinical trials, developed with input from statisticians, previous guideline authors, journal editors, regulators, and funders., Design: Funders and regulators (n = 39) of randomized trials were contacted and the literature was searched to identify existing guidance; a survey of current practice was conducted across the network of UK Clinical Research Collaboration-registered trial units (n = 46, 1 unit had 2 responders) and a Delphi survey (n = 73 invited participants) was conducted to establish consensus on SAPs. The Delphi survey was sent to statisticians in trial units who completed the survey of current practice (n = 46), CONSORT (Consolidated Standards of Reporting Trials) and SPIRIT (Standard Protocol Items: Recommendations for Interventional Trials) guideline authors (n = 16), pharmaceutical industry statisticians (n = 3), journal editors (n = 9), and regulators (n = 2) (3 participants were included in 2 groups each), culminating in a consensus meeting attended by experts (N = 12) with representatives from each group. The guidance subsequently underwent critical review by statisticians from the surveyed trial units and members of the expert panel of the consensus meeting (N = 51), followed by piloting of the guidance document in the SAPs of 5 trials., Findings: No existing guidance was identified. The registered trials unit survey (46 responses) highlighted diversity in current practice and confirmed support for developing guidance. The Delphi survey (54 of 73, 74% participants completing both rounds) reached consensus on 42% (n = 46) of 110 items. The expert panel (N = 12) agreed that 63 items should be included in the guidance, with an additional 17 items identified as important but may be referenced elsewhere. Following critical review and piloting, some overlapping items were combined, leaving 55 items., Conclusions and Relevance: Recommendations are provided for a minimum set of items that should be addressed and included in SAPs for clinical trials. Trial registration, protocols, and statistical analysis plans are critically important in ensuring appropriate reporting of clinical trials.
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- 2017
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7. Characteristics and Dissemination of Phase 1 Trials Approved by a UK Regional Office in 2012.
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Odutayo A, Copsey B, Dutton S, Cook J, Hopewell S, and Altman DG
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- Clinical Trials, Phase I as Topic methods, Diagnosis-Related Groups, Humans, Research Design, United Kingdom, Clinical Trials, Phase I as Topic statistics & numerical data, Information Dissemination methods, Pharmaceutical Preparations administration & dosage
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- 2017
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8. Anthropometric Characterization of Impaired Fetal Growth: Risk Factors for and Prognosis of Newborns With Stunting or Wasting.
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Victora CG, Villar J, Barros FC, Ismail LC, Chumlea C, Papageorghiou AT, Bertino E, Ohuma EO, Lambert A, Carvalho M, Jaffer YA, Altman DG, Noble JA, Gravett MG, Purwar M, Frederick IO, Pang R, Bhutta ZA, and Kennedy SH
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- Body Height, Body Mass Index, Body Weight, Cross-Sectional Studies, England, Fetal Growth Retardation etiology, Follow-Up Studies, Gestational Age, Humans, Infant, Newborn, Prognosis, Risk Factors, Anthropometry methods, Fetal Development, Fetal Growth Retardation epidemiology, Infant, Low Birth Weight
- Abstract
Importance: Stunting (short length for age) and wasting (low body mass index [BMI] for age) are widely used to assess child nutrition. In contrast, newborns tend to be assessed solely based on their weight., Objective: To use recent international standards for newborn size by gestational age to assess how stunted and wasted newborns differ in terms of risk factors and prognoses., Design, Setting, and Participants: A cross-sectional study with follow-up until hospital discharge was conducted at urban sites in Brazil, China, India, Italy, Kenya, Oman, England, and the United States that are participating in the INTERGROWTH-21st Project. The study was conducted from April 27, 2009, to March 2, 2014, and the final dataset for analyses was locked on March 19, 2014., Exposures: Sociodemographic and behavioral maternal risk factors, previous pregnancy history, and maternal and fetal conditions during pregnancy were investigated as risk factors for stunting and wasting. Anthropometry at birth was used to predict for neonatal prognosis., Main Outcomes and Measures: Newborn stunting and wasting were defined as birth length and BMI for gestational age below the third centiles of the INTERGROWTH-21st standards. Prognosis was assessed through mortality before hospital discharge, admission to neonatal intensive care units, and newborn complications., Results: From the 60 206 singleton live births during the study period, we selected all newborns between 33 weeks' and 42 weeks 6 days' gestation at birth (51 200 [85%]) with reliable ultrasound dating. Stunting affected 3.8% and wasting 3.4% of all newborns; both conditions were present in 0.7% of the sample. Of the 26 conditions studied, five were more strongly associated with stunting than with wasting (reported as odds ratios [OR]; 95% CI): short maternal height (6.7; 5.1-9.0), younger maternal age (0.7; 0.5-0.9), smoking (2.8; 2.3-3.3), illicit drug use (2.3; 1.5-3.6), and clinically suspected intrauterine growth restriction (5.2; 4.5-6.0). Wasting was more strongly related than stunting with 4 newborn outcomes (neonatal intensive care stay, 6.7 [5.5-8.1]; respiratory distress syndrome, 4.0 [3.3-4.9]; transient tachypnea, 2.1 [1.5-2.9]; and no oral feeding for >24 hours, 5.0 [3.9-6.5]). Maternal gestational diabetes mellitus was protective against wasting (0.6; 0.5-0.8) but not against stunting (0.9; 0.7-1.1)., Conclusions and Relevance: Although newborn stunting and wasting share some common determinants, they are distinct phenotypes with their own risk factors and neonatal prognoses. To be consistent with the literature on infant and child nutrition, newborns should be classified using the 2 phenotypes of stunting and wasting. The distinction will help to prioritize preventive interventions and focus the management of fetal undernutrition.
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- 2015
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9. The distribution of clinical phenotypes of preterm birth syndrome: implications for prevention.
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Barros FC, Papageorghiou AT, Victora CG, Noble JA, Pang R, Iams J, Cheikh Ismail L, Goldenberg RL, Lambert A, Kramer MS, Carvalho M, Conde-Agudelo A, Jaffer YA, Bertino E, Gravett MG, Altman DG, Ohuma EO, Purwar M, Frederick IO, Bhutta ZA, Kennedy SH, and Villar J
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- Anthropometry, Cross-Sectional Studies, Female, Gestational Age, Humans, Infant, Newborn, Male, Phenotype, Pregnancy, Prevalence, Prospective Studies, Risk Factors, Hospitalization statistics & numerical data, Premature Birth epidemiology, Premature Birth prevention & control
- Abstract
Importance: Preterm birth has been difficult to study and prevent because of its complex syndromic nature., Objective: To identify phenotypes of preterm delivery syndrome in the Newborn Cross-Sectional Study of the INTERGROWTH-21st Project., Design, Setting, and Participants: A population-based, multiethnic, cross-sectional study conducted at 8 geographically demarcated sites in Brazil, China, India, Italy, Kenya, Oman, the United Kingdom, and the United States. A total of 60,058 births over a 12-month fixed period between April 27, 2009, and March 2, 2014. Of these, 53,871 had an ultrasonography estimate of gestational age, among which 5828 were preterm births (10.8%). Pregnancies were prospectively studied using a standardized data collection and online data management system. Newborns had anthropometric and clinical examinations using standardized methods and identical equipment and were followed up until hospital discharge., Main Outcomes and Measures: The main study outcomes were clusters of preterm phenotypes and for each cluster, we analyzed signs of presentation at hospital admission, admission rates for neonatal intensive care for 7 days or more, and neonatal mortality rates., Results: Twelve preterm birth clusters were identified using our conceptual framework. Eleven consisted of combinations of conditions known to be associated with preterm birth, 10 of which were dominated by a single condition. However, the most common single cluster (30.0% of the total preterm cases; n = 1747) was not associated with any severe maternal, fetal, or placental condition that was clinically detectable based on the information available; within this cluster, many cases were caregiver initiated. Only 22% (n = 1284) of all the preterm births occurred spontaneously without any of these severe conditions. Maternal presentation on hospital admission, newborn anthropometry, and risk for death before hospital discharge or admission for 7 or more days to a neonatal intensive care unit, none of which were used to construct the clusters, also differed according to the identified phenotypes. The prevalence of preterm birth ranged from 8.2% in Muscat, Oman, and Oxford, England, to 16.6% in Seattle, Washington., Conclusions and Relevance: We identified 12 preterm birth phenotypes associated with different patterns of neonatal outcomes. In 22% of all preterm births, parturition started spontaneously and was not associated with any of the phenotypic conditions considered. We believe these results contribute to an improved understanding of this complex syndrome and provide an empirical basis to focus research on a more homogenous set of phenotypes.
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- 2015
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10. Association of cardiovascular trial registration with positive study findings: Epidemiological Study of Randomized Trials (ESORT).
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Emdin C, Odutayo A, Hsiao A, Shakir M, Hopewell S, Rahimi K, and Altman DG
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- Cardiovascular Diseases therapy, Humans, Publication Bias, Randomized Controlled Trials as Topic
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- 2015
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11. Association between analytic strategy and estimates of treatment outcomes in meta-analyses.
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Dechartres A, Altman DG, Trinquart L, Boutron I, and Ravaud P
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- Confidence Intervals, Humans, Odds Ratio, Randomized Controlled Trials as Topic, Research Design, Meta-Analysis as Topic, Treatment Outcome
- Abstract
Importance: A persistent dilemma when performing meta-analyses is whether all available trials should be included in the meta-analysis., Objectives: To compare treatment outcomes estimated by meta-analysis of all trials and several alternative analytic strategies: single most precise trial (ie, trial with the narrowest confidence interval), meta-analysis restricted to the 25% largest trials, limit meta-analysis (a meta-analysis model adjusted for small-study effect), and meta-analysis restricted to trials at low overall risk of bias., Data Sources: One hundred sixty-three meta-analyses published between 2008 and 2010 in high-impact-factor journals and between 2011 and 2013 in the Cochrane Database of Systematic Reviews: 92 (705 randomized clinical trials [RCTs]) with subjective outcomes and 71 (535 RCTs) with objective outcomes., Data Synthesis: For each meta-analysis, the difference in treatment outcomes between meta-analysis of all trials and each alternative strategy, expressed as a ratio of odds ratios (ROR), was assessed considering the dependency between strategies. A difference greater than 30% was considered substantial. RORs were combined by random-effects meta-analysis models to obtain an average difference across the sample. An ROR greater than 1 indicates larger treatment outcomes with meta-analysis of all trials. Subjective and objective outcomes were analyzed separately., Results: Treatment outcomes were larger in the meta-analysis of all trials than in the single most precise trial (combined ROR, 1.13 [95% CI, 1.07-1.19]) for subjective outcomes and 1.03 (95% CI, 1.01-1.05) for objective outcomes). The difference in treatment outcomes between these strategies was substantial in 47 of 92 (51%) meta-analyses of subjective outcomes (meta-analysis of all trials showing larger outcomes in 40/47) and in 28 of 71 (39%) meta-analyses of objective outcomes (meta-analysis of all trials showing larger outcomes in 21/28). The combined ROR for subjective and objective outcomes was, respectively, 1.08 (95% CI, 1.04-1.13) and 1.03 (95% CI, 1.00-1.06) when comparing meta-analysis of all trials and meta-analysis of the 25% largest trials, 1.17 (95% CI, 1.11-1.22) and 1.13 (95% CI, 0.82-1.55) when comparing meta-analysis of all trials and limit meta-analysis, and 0.94 (95% CI, 0.86-1.04) and 1.03 (95% CI, 1.00-1.06) when comparing meta-analysis of all trials and meta-analysis restricted to trials at low risk of bias., Conclusions and Relevance: Estimation of treatment outcomes in meta-analyses differs depending on the strategy used. This instability in findings can result in major alterations in the conclusions derived from the analysis and underlines the need for systematic sensitivity analyses.
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- 2014
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12. Reporting noninferiority trials--reply.
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Pocock SJ, Piaggio G, and Altman DG
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- Data Interpretation, Statistical, Endpoint Determination, Randomized Controlled Trials as Topic
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- 2013
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13. Reporting of patient-reported outcomes in randomized trials: the CONSORT PRO extension.
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Calvert M, Blazeby J, Altman DG, Revicki DA, Moher D, and Brundage MD
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- Checklist, Endpoint Determination, Health Status, Humans, Outcome Assessment, Health Care statistics & numerical data, Proxy, Quality of Life, Reproducibility of Results, Outcome Assessment, Health Care standards, Patient Participation, Randomized Controlled Trials as Topic standards, Randomized Controlled Trials as Topic statistics & numerical data
- Abstract
The CONSORT (Consolidated Standards of Reporting Trials) Statement aims to improve the reporting of randomized controlled trials (RCTs); however, it lacks guidance on the reporting of patient-reported outcomes (PROs), which are often inadequately reported in trials, thus limiting the value of these data. In this article, we describe the development of the CONSORT PRO extension based on the methodological framework for guideline development proposed by the Enhancing the Quality and Transparency of Health Research (EQUATOR) Network. Five CONSORT PRO checklist items are recommended for RCTs in which PROs are primary or important secondary end points. These recommendations urge that the PROs be identified as a primary or secondary outcome in the abstract, that a description of the hypothesis of the PROs and relevant domains be provided (ie, if a multidimensional PRO tool has been used), that evidence of the PRO instrument's validity and reliability be provided or cited, that the statistical approaches for dealing with missing data be explicitly stated, and that PRO-specific limitations of study findings and generalizability of results to other populations and clinical practice be discussed. Examples and an updated CONSORT flow diagram with PRO items are provided. It is recommended that the CONSORT PRO guidance supplement the standard CONSORT guidelines for reporting RCTs with PROs as primary or secondary outcomes. Improved reporting of PRO data should facilitate robust interpretation of the results from RCTs and inform patient care.
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- 2013
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14. Reporting of effect direction and size in abstracts of systematic reviews.
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Beller EM, Glasziou PP, Hopewell S, and Altman DG
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- Research Design, Abstracting and Indexing standards, Data Interpretation, Statistical, Review Literature as Topic
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- 2011
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15. Reporting and interpretation of randomized controlled trials with statistically nonsignificant results for primary outcomes.
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Boutron I, Dutton S, Ravaud P, and Altman DG
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- Bias, Treatment Outcome, Publishing statistics & numerical data, Randomized Controlled Trials as Topic
- Abstract
Context: Previous studies indicate that the interpretation of trial results can be distorted by authors of published reports., Objective: To identify the nature and frequency of distorted presentation or "spin" (ie, specific reporting strategies, whatever their motive, to highlight that the experimental treatment is beneficial, despite a statistically nonsignificant difference for the primary outcome, or to distract the reader from statistically nonsignificant results) in published reports of randomized controlled trials (RCTs) with statistically nonsignificant results for primary outcomes., Data Sources: March 2007 search of MEDLINE via PubMed using the Cochrane Highly Sensitive Search Strategy to identify reports of RCTs published in December 2006., Study Selection: Articles were included if they were parallel-group RCTs with a clearly identified primary outcome showing statistically nonsignificant results (ie, P > or = .05)., Data Extraction: Two readers appraised each selected article using a pretested, standardized data abstraction form developed in a pilot test., Results: From the 616 published reports of RCTs examined, 72 were eligible and appraised. The title was reported with spin in 13 articles (18.0%; 95% confidence interval [CI], 10.0%-28.9%). Spin was identified in the Results and Conclusions sections of the abstracts of 27 (37.5%; 95% CI, 26.4%-49.7%) and 42 (58.3%; 95% CI, 46.1%-69.8%) reports, respectively, with the conclusions of 17 (23.6%; 95% CI, 14.4%-35.1%) focusing only on treatment effectiveness. Spin was identified in the main-text Results, Discussion, and Conclusions sections of 21 (29.2%; 95% CI, 19.0%-41.1%), 31 (43.1%; 95% CI, 31.4%-55.3%), and 36 (50.0%; 95% CI, 38.0%-62.0%) reports, respectively. More than 40% of the reports had spin in at least 2 of these sections in the main text., Conclusion: In this representative sample of RCTs published in 2006 with statistically nonsignificant primary outcomes, the reporting and interpretation of findings was frequently inconsistent with the results.
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- 2010
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16. Effect size estimation as an essential component of statistical analysis.
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Vedula SS and Altman DG
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- Humans, Models, Statistical, Odds Ratio, Randomized Controlled Trials as Topic, Sample Size
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- 2010
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17. Comparison of registered and published primary outcomes in randomized controlled trials.
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Mathieu S, Boutron I, Moher D, Altman DG, and Ravaud P
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- Bibliometrics, Periodicals as Topic standards, Publishing standards, Publishing statistics & numerical data, Randomized Controlled Trials as Topic standards, Treatment Outcome, Periodicals as Topic statistics & numerical data, Publication Bias, Randomized Controlled Trials as Topic statistics & numerical data, Registries standards
- Abstract
Context: As of 2005, the International Committee of Medical Journal Editors required investigators to register their trials prior to participant enrollment as a precondition for publishing the trial's findings in member journals., Objective: To assess the proportion of registered trials with results recently published in journals with high impact factors; to compare the primary outcomes specified in trial registries with those reported in the published articles; and to determine whether primary outcome reporting bias favored significant outcomes., Data Sources and Study Selection: MEDLINE via PubMed was searched for reports of randomized controlled trials (RCTs) in 3 medical areas (cardiology, rheumatology, and gastroenterology) indexed in 2008 in the 10 general medical journals and specialty journals with the highest impact factors., Data Extraction: For each included article, we obtained the trial registration information using a standardized data extraction form., Results: Of the 323 included trials, 147 (45.5%) were adequately registered (ie, registered before the end of the trial, with the primary outcome clearly specified). Trial registration was lacking for 89 published reports (27.6%), 45 trials (13.9%) were registered after the completion of the study, 39 (12%) were registered with no or an unclear description of the primary outcome, and 3 (0.9%) were registered after the completion of the study and had an unclear description of the primary outcome. Among articles with trials adequately registered, 31% (46 of 147) showed some evidence of discrepancies between the outcomes registered and the outcomes published. The influence of these discrepancies could be assessed in only half of them and in these statistically significant results were favored in 82.6% (19 of 23)., Conclusion: Comparison of the primary outcomes of RCTs registered with their subsequent publication indicated that selective outcome reporting is prevalent.
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- 2009
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18. Risk stratification for in-hospital mortality in acutely decompensated heart failure.
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Royston P and Altman DG
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- Humans, Models, Statistical, Heart Failure mortality, Hospital Mortality, Risk Assessment
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- 2005
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19. Empirical evidence for selective reporting of outcomes in randomized trials: comparison of protocols to published articles.
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Chan AW, Hróbjartsson A, Haahr MT, Gøtzsche PC, and Altman DG
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- Clinical Protocols, Meta-Analysis as Topic, Registries, Publication Bias, Randomized Controlled Trials as Topic standards, Treatment Outcome
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Context: Selective reporting of outcomes within published studies based on the nature or direction of their results has been widely suspected, but direct evidence of such bias is currently limited to case reports., Objective: To study empirically the extent and nature of outcome reporting bias in a cohort of randomized trials., Design: Cohort study using protocols and published reports of randomized trials approved by the Scientific-Ethical Committees for Copenhagen and Frederiksberg, Denmark, in 1994-1995. The number and characteristics of reported and unreported trial outcomes were recorded from protocols, journal articles, and a survey of trialists. An outcome was considered incompletely reported if insufficient data were presented in the published articles for meta-analysis. Odds ratios relating the completeness of outcome reporting to statistical significance were calculated for each trial and then pooled to provide an overall estimate of bias. Protocols and published articles were also compared to identify discrepancies in primary outcomes., Main Outcome Measures: Completeness of reporting of efficacy and harm outcomes and of statistically significant vs nonsignificant outcomes; consistency between primary outcomes defined in the most recent protocols and those defined in published articles., Results: One hundred two trials with 122 published journal articles and 3736 outcomes were identified. Overall, 50% of efficacy and 65% of harm outcomes per trial were incompletely reported. Statistically significant outcomes had a higher odds of being fully reported compared with nonsignificant outcomes for both efficacy (pooled odds ratio, 2.4; 95% confidence interval [CI], 1.4-4.0) and harm (pooled odds ratio, 4.7; 95% CI, 1.8-12.0) data. In comparing published articles with protocols, 62% of trials had at least 1 primary outcome that was changed, introduced, or omitted. Eighty-six percent of survey responders (42/49) denied the existence of unreported outcomes despite clear evidence to the contrary., Conclusions: The reporting of trial outcomes is not only frequently incomplete but also biased and inconsistent with protocols. Published articles, as well as reviews that incorporate them, may therefore be unreliable and overestimate the benefits of an intervention. To ensure transparency, planned trials should be registered and protocols should be made publicly available prior to trial completion.
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- 2004
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20. Analysis and reporting of factorial trials: a systematic review.
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McAlister FA, Straus SE, Sackett DL, and Altman DG
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- Data Interpretation, Statistical, Randomized Controlled Trials as Topic methods, Randomized Controlled Trials as Topic statistics & numerical data, Research Design
- Abstract
Context: Although factorial trials have become common, standards for the analysis and reporting of such trials have not been established and, despite concerns about the possibility of unrecognized interactions between therapies in factorial trials, the magnitude of this potential problem is unknown., Objective: To examine the rationale, methods, and analysis of randomized factorial trials., Data Sources and Study Selection: We searched MEDLINE, EMBASE, and the Cochrane Controlled Trials Register using the terms factorial, interaction, 2 x 2, 2 by 2, and incremental to identify factorial randomized trials published from January 2000 to July 2002. To identify trials missed by the electronic search, we performed a hand search of English-language trials in a defined topic area (using the term myocardial ischemia [exp]) listed in MEDLINE (1966-2002), EMBASE (1980-2002), and the Cochrane Controlled Trials Register, as well as all trials in any topic area published in December 2000, excluding trials reporting only continuous surrogate end points. The final set of 33 eligible publications described 29 unique trials., Data Extraction: Two investigators independently identified factorial trials, generated a list of items affecting validity of results, and abstracted these items from each trial., Data Synthesis: The sensitivity of electronic searching for identifying factorial trials was 76%. Our 3-pronged search strategy identified 44 factorial trials with clinically important binary outcomes: 36 (82%) were done for reasons of efficiency (testing 2 interventions in the same patient population), and 8 (18%) were done to assess the incremental benefits of combining the 2 treatments. All but 1 of the trials reported treatment effects by comparing all patients who received treatment A (ie, those receiving either A alone or both A and B) vs all those not receiving treatment A (ie, those receiving either B alone or neither A nor B). Twenty-nine of the 44 trials (66%) reported the data from each of the treatment groups separately; 26 trials (59%) reported testing for interactions between the treatments. Only 2 of 31 (6%) comparisons demonstrated a statistically significant interaction between the 2 treatments., Conclusions: Accurate interpretation of factorial trials depends on the transparent reporting of data for each treatment cell. Despite concerns about unrecognized interactions, our findings suggest that investigators are appropriately restricting their use of the factorial design to those situations in which 2 (or more) treatments do not have the potential for substantive interaction.
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- 2003
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21. Allocation concealment in clinical trials.
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Schulz KF, Altman DG, and Moher D
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- Bias, Random Allocation, Meta-Analysis as Topic, Randomized Controlled Trials as Topic
- Published
- 2002
22. Interpreting the number needed to treat.
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Schulz KF, Moher D, and Altman DG
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- Data Interpretation, Statistical, Randomized Controlled Trials as Topic statistics & numerical data
- Published
- 2002
23. How statistical expertise is used in medical research.
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Altman DG, Goodman SN, and Schroter S
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- Authorship, Data Interpretation, Statistical, Manuscripts, Medical as Topic, Peer Review, Research standards, Research Design, Statistics as Topic
- Abstract
Context: Investigation of the nature and frequency of statistician involvement in medical research and its relation to the final editorial decision., Methods: Authors of original research articles who submitted to BMJ and Annals of Internal Medicine from May through August 2001 were sent a short questionnaire at the time of manuscript submission. Authors were asked if they received assistance from a person with statistical expertise, the nature of any such contribution, and reasons why, if no statistical input was received., Results: The response rate was 75% (704/943); methodological input was reported for 514 (73%) of these papers. In 435 papers (85%), such input was provided by biostatisticians or epidemiologists and, if deemed significant, was typically associated with authorship. A total of 33 of 122 methodologists (27%) whose main contribution started at the analysis stage received neither acknowledgment nor authorship. Research without methodological assistance was more likely to be rejected without review (71% vs 57%; chi(2) = 10.6; P =.001) and possibly less likely to be accepted for publication (7% vs 11%; chi(2) = 2.37; P =.12)., Conclusions: Statistical input to medical research is widely recommended but inconsistently obtained. Individuals providing such expertise are often not involved until the analysis of data and many go unrecognized by either authorship or acknowledgment.
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- 2002
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24. Poor-quality medical research: what can journals do?
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Altman DG
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- Randomized Controlled Trials as Topic, Research Design, Peer Review, Research, Publication Bias
- Abstract
The aim of medical research is to advance scientific knowledge and hence--directly or indirectly--lead to improvements in the treatment and prevention of disease. Each research project should continue systematically from previous research and feed into future research. Each project should contribute beneficially to a slowly evolving body of research. A study should not mislead; otherwise it could adversely affect clinical practice and future research. In 1994 I observed that research papers commonly contain methodological errors, report results selectively, and draw unjustified conclusions. Here I revisit the topic and suggest how journal editors can help.
- Published
- 2002
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25. A meta-analysis of hormone replacement therapy for fracture prevention.
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Altman DG
- Subjects
- Data Interpretation, Statistical, Female, Humans, Estrogen Replacement Therapy, Fractures, Bone prevention & control, Meta-Analysis as Topic, Osteoporosis, Postmenopausal prevention & control, Random Allocation
- Published
- 2001
26. Empirical evidence of bias. Dimensions of methodological quality associated with estimates of treatment effects in controlled trials.
- Author
-
Schulz KF, Chalmers I, Hayes RJ, and Altman DG
- Subjects
- Clinical Protocols, Models, Statistical, Quality Control, Randomized Controlled Trials as Topic statistics & numerical data, Research Design, Bias, Randomized Controlled Trials as Topic standards
- Abstract
Objective: To determine if inadequate approaches to randomized controlled trial design and execution are associated with evidence of bias in estimating treatment effects., Design: An observational study in which we assessed the methodological quality of 250 controlled trials from 33 meta-analyses and then analyzed, using multiple logistic regression models, the associations between those assessments and estimated treatment effects., Data Sources: Meta-analyses from the Cochrane Pregnancy and Childbirth Database., Main Outcome Measures: The associations between estimates of treatment effects and inadequate allocation concealment, exclusions after randomization, and lack of double-blinding., Results: Compared with trials in which authors reported adequately concealed treatment allocation, trials in which concealment was either inadequate or unclear (did not report or incompletely reported a concealment approach) yielded larger estimates of treatment effects (P < .001). Odds ratios were exaggerated by 41% for inadequately concealed trials and by 30% for unclearly concealed trials (adjusted for other aspects of quality). Trials in which participants had been excluded after randomization did not yield larger estimates of effects, but that lack of association may be due to incomplete reporting. Trials that were not double-blind also yielded larger estimates of effects (P = .01), with odds ratios being exaggerated by 17%., Conclusions: This study provides empirical evidence that inadequate methodological approaches in controlled trials, particularly those representing poor allocation concealment, are associated with bias. Readers of trial reports should be wary of these pitfalls, and investigators must improve their design, execution, and reporting of trials.
- Published
- 1995
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27. Assessing the quality of randomization from reports of controlled trials published in obstetrics and gynecology journals.
- Author
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Schulz KF, Chalmers I, Grimes DA, and Altman DG
- Subjects
- Gynecology, Obstetrics, Quality Control, Randomized Controlled Trials as Topic methods, Periodicals as Topic, Random Allocation, Randomized Controlled Trials as Topic standards
- Abstract
Objective: To assess the methodologic quality of approaches used to allocate participants to comparison groups in randomized controlled trials from one medical specialty., Design: Survey of published, parallel group randomized controlled trials., Data Sources: All 206 reports with allocation described as randomized from the 1990 and 1991 volumes of four journals of obstetrics and gynecology., Main Outcome Measures: Direct and indirect measures of the adequacy of randomization and baseline comparisons., Results: Only 32% of the reports described an adequate method for generating a sequence of random numbers, and only 23% contained information showing that steps had been taken to conceal assignment until the point of treatment allocation. A mere 9% described both sequence generation and allocation concealment. In reports of trials that had apparently used unrestricted randomization, the differences in sample sizes between treatment and control groups were much smaller than would be expected due to chance. In reports of trials in which hypothesis tests had been used to compare baseline characteristics, only 2% of reported test results were statistically significant, lower than the expected rate of 5%., Conclusions: Proper randomization is required to generate unbiased comparison groups in controlled trials, yet the reports in these journals usually provided inadequate or unacceptable information on treatment allocation. Additional analyses suggest that nonrandom manipulation of comparison groups and selective reporting of baseline comparisons may have occurred.
- Published
- 1994
28. Is there a case for an international medical scientific press council?
- Author
-
Altman DG, Chalmers I, and Herxheimer A
- Subjects
- Advisory Committees, Authorship, Biomedical Research, Internationality, Editorial Policies, International Cooperation, Professional Misconduct, Publishing standards, Scientific Misconduct
- Abstract
Serious abuse of editorial power is rarely publicized, but evidence that it occurs is accumulating. Authors who believe that they have been dealt with unfairly have little possibility of a hearing of their complaint, and cases cannot easily be publicized because of fears of legal action. We describe briefly three cases in which the alleged misdeeds indicate that there were legitimate questions that needed answers. In the first case, an editor republished a previously published article without the authors' permission (but stated the opposite), attacked it in an accompanying editorial, and then denied the authors the right of reply. The other cases concerned a commissioned review article that was plagiarized and an editor with an undisclosed vested interest. An appeal process is needed for authors who think that they are victims of editorial abuse of power. We suggest that the International Committee of Medical Journal Editors turn its attention to editorial misconduct and explore possible procedures for allowing authors' grievances to be heard and for possible sanctions if complaints are upheld. An International Medical Scientific Press Council might be established to produce a code of conduct for editors and a corresponding taxonomy of inappropriate editorial behavior.
- Published
- 1994
29. Transfer of technology from statistical journals to the biomedical literature. Past trends and future predictions.
- Author
-
Altman DG and Goodman SN
- Subjects
- Forecasting, Periodicals as Topic trends, Publishing trends, Statistics as Topic methods, Statistics as Topic trends
- Abstract
Objective: To investigate the speed of the transfer of new statistical methods into the medical literature and, on the basis of current data, to predict what methods medical journal editors should expect to see in the next decade., Design: Influential statistical articles were identified and the time pattern of citations in the medical literature was ascertained. In addition, longitudinal studies of the statistical content of articles in medical journals were reviewed., Main Outcome Measures: Cumulative number of citations in medical journals of each article in the years after publication., Results: Annual citations show some evidence of decreasing lag times between the introduction of new statistical methods and their appearance in medical journals. Newer technical innovations still typically take 4 to 6 years before they achieve 25 citations in the medical literature. Few methodological advances of the 1980s seem yet to have been widely cited in medical journals. Longitudinal studies indicate a large increase in the use of more complex statistical methods., Conclusions: Time trends suggest that technology diffusion has speeded up during the last 30 years, although there is still a lag of several years before medical citations begin to accrue. Journals should expect to see more articles using increasingly sophisticated methods. Medical journals may need to modify reviewing procedures to deal with articles using these complex new methods.
- Published
- 1994
30. Predictors of physician's smoking cessation advice.
- Author
-
Frank E, Winkleby MA, Altman DG, Rockhill B, and Fortmann SP
- Subjects
- Adolescent, Adult, Aged, Bias, California epidemiology, Child, Counseling, Cross-Sectional Studies, Female, Humans, Male, Middle Aged, Prevalence, Sampling Studies, Smoking ethnology, Health Education, Physician's Role, Smoking Cessation, Smoking Prevention
- Abstract
Objectives: To determine the percentage of smokers reporting that a physician had ever advised them to smoke less or to stop smoking, and the effect of time, demographics, medical history, and cigarette dependence on the likelihood that respondents would state that a physician had ever advised them to stop smoking., Design and Setting: Data were collected from the Stanford Five-City Project, a communitywide health education intervention program. The two treatment and three control cities were located in northern and central California. As there was no significant difference between treatment and control cities regarding cessation advice, data were pooled for these analyses., Participants: There were five cross-sectional, population-based Five-City Project surveys (conducted in 1979-1980, 1981-1982, 1983-1984, 1985-1986, and 1989-1990); these surveys randomly sampled households and included all residents aged 12 to 74 years., Main Outcome Measures: Improved smoking advice rates over time in all towns was an a priori hypothesis., Results: Of the 2710 current smokers, 48.8% stated that their physicians had ever advised them to smoke less or stop smoking. Respondents were more likely to have been so advised if they smoked more cigarettes per day, were surveyed later in the decade, had more office visits in the last year, or were older. In 1979-1980, 44.1% of smokers stated that they had ever been advised to smoke less or to quit by a physician, vs 49.8% of smokers in 1989-1990 (P less than .07). Only 3.6% of 1672 ex-smokers stated that their physicians had helped them to quit., Conclusion: These findings suggest that physicians still need to increase smoking cessation counseling to all patients, particularly adolescents and other young smokers, minorities, and those without cigarette-related disease.
- Published
- 1991
31. The effects of combining education and enforcement to reduce tobacco sales to minors. A study of four northern California communities.
- Author
-
Feighery E, Altman DG, and Shaffer G
- Subjects
- Adolescent, Adolescent Behavior, California epidemiology, Child, Commerce, Humans, Smoking Prevention, Health Education, Plants, Toxic, Smoking legislation & jurisprudence, Smoking Cessation statistics & numerical data, Social Control, Formal, Nicotiana
- Abstract
Objective: To examine the effects of a community education and law enforcement intervention on illegal tobacco sales to minors., Design: A 2-year, before and after trial with retail stores as the unit of analysis., Setting: Implementation occurred in four suburban California communities with populations of 25,000 to 100,000., Participants: All the retail stores in one intervention community and half the retail stores, randomly selected, in the other three intervention communities (n = 169) were visited by minors aged 14 to 16 years with the intent to purchase tobacco., Intervention: Ongoing community and merchant education and four law enforcement operations were conducted., Main Outcome Measures: Over-the-counter and vending machine sales of tobacco to minors were the primary outcomes., Results: Among a cohort of stores visited by minors at the pretest (n = 104) in June 1988, 71% sold tobacco over the counter and 92% sold tobacco through vending machines. At posttest 2 in May 1990, 24% sold tobacco over the counter and 93% sold tobacco through vending machines. Of the 31 stores issued citations, 16 were followed into the courts where the fines were dismissed or reduced., Conclusions: Education alone had a limited effect on reducing illegal tobacco sales to minors. It did promote community support for more aggressive enforcement strategies. Education plus enforcement decreased significantly over-the-counter sales; vending machine sales were unaffected by these interventions. The lack of support at the judicial level may temper the effectiveness of enforcement. Legislative remedies addressing judicial obstacles and vending machine sales are needed.
- Published
- 1991
32. Reducing the illegal sale of cigarettes to minors.
- Author
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Altman DG, Foster V, Rasenick-Douss L, and Tye JB
- Subjects
- Adolescent, Age Factors, California, Commerce, Female, Health Education methods, Humans, Male, Smoking legislation & jurisprudence, Adolescent Behavior, Smoking Prevention
- Abstract
This study reports on an effort to stop the illegal sale of cigarettes to minors. In Santa Clara County, Calif, 412 stores and 30 vending machines were visited by 18 minors aged 14 through 16 years with the intent to purchase cigarettes; they were successful at 74% of the stores and 100% of the vending machines. After an aggressive six-month campaign using communitywide media, direct merchant education, contact with the chief executive officers of chain stores and franchise operations owned by major companies, and grassroots work with community organizations, the percentage of stores with illegal over-the-counter sale of cigarettes to minors was reduced to 39%. Sales from vending machines were not reduced. While much remains to be accomplished in stopping the illegal sale of tobacco to minors, data from this study illustrate that a well-designed community and merchant education campaign can significantly reduce such sales.
- Published
- 1989
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