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Abstract Background The estimates of vaccination coverage are measured from administrative data and from population based survey. While both card-based and recall data are collected through population survey, and the recall is when the card is missing, the preferred estimates remain of the card-based due to limited validity of parental recalls. As there is a concern of missing cards in poor settings, the evidence on validity of parental recalls is limited and varied across vaccine types, and therefore timely and needed. We validated the recalls against card-based data based on population survey in Tanzania. Methods We used a cross-sectional survey of about 3000 households with women who delivered in the last 12 months prior to the interview in 2012 from three regions in Tanzania. Data on the vaccination status on four vaccine types were collected using two data sources, card and recall-based. We compared the level of agreement and identified the recall bias between the two data sources. We further computed the sensitivity and specificity of parental recalls, and used a multivariate logit model to identify the determinants of parental recall bias. Results Most parents (85.4%) were able to present the vaccination cards during the survey, and these were used for analysis. Although the coverage levels were generally similar across data sources, the recall-based data slightly overestimated the coverage estimates. The level of agreement between the two data sources was high above 94%, with minimal recall bias of less than 6%. The recall bias due to over-reporting were slightly higher than that due to under-reporting. The sensitivity of parental recalls was generally high for all vaccine types, while the specificity was generally low across vaccine types except for measles. The minimal recall bias for DPT and measles were associated with the mother’s age, education level, health insurance status, region location and child age. Conclusion Parental recalls when compared to card-based data are hugely accurate with minimal recall bias in Tanzania. Our findings support the use of parental recall collected through surveys to identify the child vaccination status in the absence of vaccination cards. The use of recall data alongside card-based estimates also ensures more representative coverage estimates.

Assessment of posttraumatic stress disorder (PTSD) has relied almost exclusively on retrospective memory of symptoms, sometimes over long intervals. This approach creates potential for recall bias and obscures the extent to which symptoms fluctuate. The aim of the present study was to examine the discrepancy between retrospective self-reporting of PTSD symptoms and ecological momentary assessment (EMA), which captures symptoms closer to when they occur. The study also sought to estimate the degree to which PTSD symptoms vary or are stable in the short-term. World Trade Center responders (N = 202) oversampled for current PTSD (19.3% met criteria in past month) were assessed three times a day for 7 consecutive days. Retrospective assessment of past week symptoms at the end of the reporting period were compared with daily EMA reports. There was correspondence between two approaches, but retrospective reports most closely reflected symptom severity on the worst day of the reporting period rather than average severity across the week. Symptoms varied significantly, even within the span of hours. Findings support intervention research efforts focused on exploiting significant, short-term variability of PTSD symptoms, and suggest that traditional assessments most reflect the worst day of symptoms over a given period of recall. [ABSTRACT FROM AUTHOR]

• Passenger behaviors in airports are examined using data collected from beacons, mobile phones, and questionnaires. • Recall errors in air passenger data with a retrospective design are not merely inaccurate but also biased. • Passenger behaviors in terminals are intercorrelated and could be grouped into moving and sedentary activities. • Passengers' time budgets are crucial to the choice of sedentary activities because of their relatively long duration. Passenger activities in terminals can be understood better in the current era, when sensors are pervasive throughout airports. This study demonstrated the usefulness of combining multiple-source data to investigate passenger behavior in airports. Objective time-use and terminal activity participation data of 266 air passengers' behavior at Taipei Songshan International Airport were collected from beacons, a self-developed mobile application, and questionnaires. The study first investigated recall errors generated from self-report questionnaires, an approach commonly used in previous studies with a retrospective design. The study then assessed the participation and duration of terminal activities conducted by passengers with standard, nested, and mixed multiple discrete-continuous extreme value models. The analysis results revealed that recall errors were associated with activity choice and duration and passenger characteristics. These errors were not random but systematic and could potentially lead to biased results in retrospective studies solely based on self-report questionnaires. The estimation results of extreme value models generally confirmed the expected association of terminal activity choice with passenger characteristics, such as more frequent retail store visits in female passengers than in male passengers. However, the associations of passenger characteristics with activity duration could be consistent with or opposite to those with activity choice; for example, frequent flyers tended to consume food and beverages (F&B) more frequently and spend a longer time in restaurants whereas passengers having a long free dwell time were less likely than those having a short free dwell time to consume F&B but the duration was relatively long on average. Managerial implications for airports and retailers and recommendations for future air passenger behavioral studies were provided. [ABSTRACT FROM AUTHOR]

Background: Headache diaries and recall questionnaires are frequently used to assess headache frequency and severity in clinical and research settings. Methods: Using 20 weeks of data from an intervention trial with 182 participants, we evaluated concordance between an electronic headache diary administered on a daily basis and designed to capture the presence and severity of headaches on an hourly basis (the headache diary) and a recall questionnaire, with retrospective estimation of the number of headache days assessed on a monthly basis. We further examined whether the duration or severity of headaches assessed by the electronic diary impacted concordance between these two measures. Results: Over the course of four 28-day periods, people with migraine participating in a dietary intervention reported an average of 13.7 and 11.1 headache days in the headache diary and recall questionnaire, respectively. Conclusion: Over time, the concordance between headache days reported in these two measures tended to increase; however, the recall questionnaire headache estimates were lower than the diary measures in all four periods. When analysis was restricted to headaches lasting 8 hours or more, the number of headache days was more closely aligned with days reported in the recall questionnaire, indicating that the accuracy of recall estimates is likely to be influenced by headache duration. Restriction of analyses to moderate-to-severe headaches did not change results as much as headache duration. The findings indicate that recall questionnaires administered on a monthly basis may underestimate headache frequency and therefore should not be used interchangeably with headache diaries. Clinical Trials.gov Identifier : NCT02012790 [ABSTRACT FROM AUTHOR]

While the use of surveys to understand perception of climate change and adaptation is common in research on agriculture, the reliability of some aspects of the methodology is largely untested. In particular, there is limited evidence on (i) the degree to which measures of perception are sensitive to questionnaire design, (ii) the accuracy of recall methods for climate change, and (iii) the degree to which measures of adaptation based on recall from one-time surveys match the historical record. Using an established panel of farmers from across Kenya and a split sample method, I test both the sensitivity of stated perceptions of climate change to question format and the accuracy of recalled adaptations. In one treatment, farmers face open-ended questions about temperature and rainfall changes while in the other treatment, farmers are offered closed-end questions. Both approaches are common in the voluminous literature on climate change adaptation. Responses are highly sensitive to question format, both in the degree of perceived change and in the types of changes. Stated adaptations are not so sensitive to question format, but still diverge. Stated adaptations do not correspond well to the historical record of farming practices over the 15 years of the panel. Overall, the evidence suggests that researchers and policy-makers should be highly cautious in their use of subjective perceptions of climate change and the use of adaptation measures based on recall data. [ABSTRACT FROM AUTHOR]

Background: The outbreak of coronavirus disease 2019 (COVID-19) caused substantial changes in lifestyle, responsibilities, and stressors. Such dramatic societal changes might cause overall sleep health to decrease (stress view), to remain unchanged (resilience view), or even to improve (reduced work/schedule burden view).Methods: We addressed this question using longitudinal, cross-sectional, and retrospective recall methodologies in 699 American adult participants in late March 2020, two weeks following the enactment of social distancing and shelter-in-place policies in the United States.Results: Relative to baseline data from mid February 2020, cross-sectional and longitudinal analyses demonstrated that average sleep quality was unchanged, or even improved, early in the pandemic. However, there were clear individual differences: approximately 25% of participants reported that their sleep quality had worsened, which was explained by stress vulnerability, caregiving, adverse life impact, shift work, and presence of COVID-19 symptoms.Conclusions: Therefore, the COVID-19 pandemic has detrimentally impacted some individuals' sleep health while paradoxically benefited other individuals' sleep health by reducing rigid work/school schedules such as early morning commitments. [ABSTRACT FROM AUTHOR]

Objective: Anchor‐based methods to calculate the minimal clinically important difference (MCID) of a patient‐reported outcome measure (PROM) may suffer from recall bias. This has never been investigated for otolaryngic PROMs. We sought to identify evidence of recall bias in calculation of MCIDs of PROMs for patients with chronic rhinosinusitis (CRS). Design: Retrospective analysis of data from two previous studies calculating the MCID of the 22‐item Sinonasal Outcome Test (SNOT‐22) and 5‐dimensonal EuroQol questionnaire (EQ‐5D) in CRS patients. Setting: Tertiary rhinology clinic. Participants: Adults with CRS. Main outcome measures: SNOT‐22 score, and EQ‐5D visual analog scale scores (EQ‐5D VAS) and health utility values (EQ‐5D HUV) before and after medical treatment for CRS. After treatment, participants were asked to rate the change in sinonasal symptoms and general health (the anchor question) as "Much worse," "A little worse," "About the same," "A little better" or "Much better." Participants' responses to the anchor question were checked for association with post‐treatment and pre‐treatment scores using ordinal regression. Results: On univariate association, post‐treatment SNOT‐22 and EQ‐5D scores were associated with respective participants' anchor question responses (P <.001 in all cases). Only pre‐treatment SNOT‐22 score was associated with anchor question responses (P =.017) on univariate association, in contrast to pre‐treatment EQ‐5D scores. Pre‐treatment EQ‐5D scores only associated with anchor question responses when controlling for post‐treatment scores. Conclusion: The anchor‐based MCIDs of the SNOT‐22, which reflects disease‐specific QOL, and the EQ‐5D, which reflects general health‐related QOL, appear to be largely free of recall bias. [ABSTRACT FROM AUTHOR]

Individuals' recall of past emotions is often biased. Previous studies have focused on personality dispositions as predictors of such bias, but not yet on event-level (within-person) predictors (beyond the valence of emotions). We investigated whether personally more relevant events and higher momentary clarity of the elicited emotions yield less recall bias. To indicate emotional clarity, we used a response-time-based measure. We also examined whether extraversion, neuroticism, and conscientiousness would predict between-person differences in recall bias. The results of an experience sampling study (534 events nested in 72 individuals) showed that, on average, positive emotions were retrospectively overestimated, whereas negative emotions were recalled more accurately. Multilevel models revealed that negative emotions were overestimated for events characterized by lower personal relevance and lower momentary emotional clarity. On the person level, higher conscientiousness was related to a smaller recall bias for positive and negative emotions. The findings suggest that the accuracy of retrospective judgments of emotions varies systematically both within and between persons. [ABSTRACT FROM AUTHOR]

Background: The gold-standard method for collecting patient-reported outcomes (PROs) is the prospective assessment of preoperative to postoperative change. However, this method is not always feasible because of unforeseen cases or emergencies, logistical and infrastructure barriers, and cost issues. In such cases, a retrospective approach serves as a potential alternative, but there are conflicting conclusions regarding the reliability of the recalled preoperative PROs after orthopaedic procedures. Purpose: To assess the agreement between prospectively and retrospectively collected PROs for a common, low-risk procedure. Study Design: Cohort study (Diagnosis); Level of evidence, 3. Methods: Patients who underwent arthroscopic rotator cuff repair between May 2012 and September 2017 at the study institution were identified. All of the patients completed the American Shoulder and Elbow Surgeons (ASES) Standard Shoulder Assessment Form preoperatively at their preassessment appointment. Patients were then contacted in the postoperative period and asked to recall their preoperative condition while completing another ASES form. Results: A total of 84 patients completed the telephone survey and were included in this analysis (mean age, 57.40 ± 9.96 years). The mean duration of time from onset of shoulder symptoms to surgery was 9.13 ± 9.08 months. The mean duration of time between surgery and recall ASES administration was 39.12 ± 17.37 months. The mean recall ASES score was significantly lower than the preoperative ASES score (30.69 ± 16.93 vs 51.42 ± 19.14; P <.001). There was poor test-retest reliability between preoperative ASES and recall ASES (intraclass correlation coefficient, 0.292; 95% CI, –0.07, 0.57; P =.068). Greater age at the time of recall, a shorter symptomatic period before surgery, and less severe preoperative shoulder dysfunction were associated with a greater difference between preoperative ASES and recall ASES. Conclusion: Retrospectively reported PROs are subject to significant recall bias. Recalled PROs were almost always lower than their prospectively recorded counterparts. Recalled PROs are more likely to be accurate when reported by younger patients, those with a longer duration of symptoms, and those with more severe preoperative conditions. [ABSTRACT FROM AUTHOR]

There has been considerable public interest in the topic of traumatic brain injury (TBI) as a risk factor for development of late-life dementia. A review was performed on empirical studies examining the relationship between these two conditions. Although results from a number of studies clearly demonstrate that TBI is a positive risk factor for developing dementia, there are an equivalent number of studies that obtain inconclusive or negative findings. Inconsistencies across studies are often the result of methodological findings including the nature of the investigational design, choice of comparison groups, and criteria used to define cases. In many studies, the diagnosis of TBI is obtained retrospectively in a manner that is subject to bias. Accurate identification of dementia cases is often compromised by the use of inappropriately brief follow-up periods and variations in diagnostic methods. There remains no universally accepted neurobiological mechanism to explain the transition from acute TBI to the chronic effects of dementia. Studies of specialty populations, including athletes and military personnel are beset by secular and cohort effects, raising questions about the applicability of findings to the general population. No existing studies have been able to exclude the possible effects of confounding medical or lifestyle factors in facilitating the onset of dementia following TBI. Although the research findings suggest a general association between TBI and dementia, the specifics of the relationship remain poorly defined. [ABSTRACT FROM AUTHOR]

Visceroception is a complex phenomenon comprising the sensation, interpretation, and integration of sensations along the gut-brain axis, including pain or defecatory urgency. Stress is considered a crucial risk factor for the development and maintenance of disorders of gut-brain signaling, which are characterized by altered visceroception. Although the broad role of stress and stress mediators in disturbed visceroception is widely acknowledged, the putative contribution of chronic stress to variations in normal visceroception remains incompletely understood. We aimed to elucidate the role of chronic stress in shaping different facets of visceroception. From a well-characterized, large sample of healthy men and women (N = 180, 50% female), volunteers presenting with low (n = 57) and elevated (n = 61) perceived chronic stress were identified based on the validated Trier Inventory for Chronic Stress (TICS). Visceral sensitivity together with perceived and recalled intensity and defecatory urgency induced by repeated rectal distensions was experimentally assessed, and compared between low and elevated stress groups. Subgroups were compared regarding state anxiety and salivary cortisol concentrations across experimental phases and with respect to psychological measures. Finally, in the full sample and in chronic stress subgroups, a recall bias in terms of a discrepancy between the perception of experimentally-induced symptoms and their recall was tested. Participants with elevated chronic stress presented with increased state anxiety and higher cortisol concentrations throughout the experimental phases compared to the group with low chronic stress. Group differences in visceral sensitivity were not evident. The elevated stress group perceived significantly higher urgency during the stimulation phase, and recalled substantially higher feelings of urgency induced by rectal distensions, while perceived and recalled intensity were comparable between groups. Volunteers with elevated stress exhibited a recall bias in terms of a higher recall relative to mean perception of urgency, whereas no such bias was observed for the intensity of experimental visceral stimulation. Our findings in healthy men and women provide first evidence that the troublesome symptom of urgency might be particularly modifiable by chronic stress and support the relevance of memory biases in visceroception. These results may help to disentangle the impact of chronic stress on altered visceroception in disturbances of gut-brain communication. [ABSTRACT FROM AUTHOR]

Background: Physical activity recall instruments provide an inexpensive method of collecting physical activity patterns on a sample of individuals, but they are subject to systematic and random measurement error. Statistical models can be used to estimate measurement error in activity recalls and provide more accurate estimates of usual activity parameters for a population. Methods: We develop a measurement error model for a short-term activity recall that describes the relationship between the recall and an individual's usual activity over a long period of time. The model includes terms for systematic and random measurement errors. To estimate model parameters, the design should include replicate observations of a concurrent activity recall and an objective monitor measurement on a subsample of respondents. Results: We illustrate the approach with preliminary data from the Iowa Physical Activity Measurement Study. In this dataset, recalls tend to overestimate actual activity, and measurement errors greatly increase the variance of recalls relative to the person-to-person variation in usual activity. Statistical adjustments are used to remove bias and extraneous variation in estimating the usual activity distribution. Conclusions: Modeling measurement error in recall data can be used to provide more accurate estimates of long-term activity behavior. [ABSTRACT FROM AUTHOR]

Because of their efficiency and ability to keep many other factors constant, twin studies have a special appeal for investigators. Just as with any teaching dataset, a “matched-sets” dataset used to illustrate a statistical model should be compelling, still relevant, and valid. Indeed, such a “model dataset” should meet the same tests for worthiness that news organization editors impose on their journalists: are the data new? Are they true? Do they matter? This article introduces and shares a twin dataset that meets, to a large extent, these criteria. In fact, while more than two decades old, the data are still widely cited today in ongoing related research. This dataset was the basis of a clever study that confirmed an inspired hunch, changed the way pregnancies in HIV-positive mothers are managed, and led to reductions in the rates of maternal-to-child transmission of HIV.

The peak-end memory bias has been well documented for the retrospective evaluation of pain. It describes that the retrospective evaluation of pain is largely based on the discomfort experienced at the most intense point (peak) and at the end of the episode. This is notable because it means that longer episodes with a better ending can be remembered as less aversive than shorter ones; this is even if the former had the same peak in painfulness and an overall longer duration of pain. Until now, this bias has not been studied in the domain of anxiety despite the high relevance of variable levels of anxiety in the treatment of anxiety disorders. Therefore, we set out to replicate the original studies but with an induction of variable levels of anxiety. Of 64 women, half watched a clip from a horror movie which ended at the most frightening moment. The other half watched an extended version of this clip with a moderately frightening ending. Afterward, all participants were asked to rate the global anxiety which was elicited by the video. When the film ended at the most frightening moment, participants retrospectively reported more anxiety than participants who watched the extended version. This is the first study to document that the peak-end bias can be found in the domain of anxiety. These findings require replication and extension to a treatment context to evaluate its implications for exposure therapy.

Background: Sacroiliac joint (SIJ) injections are crucial in the diagnostic toolkit for evaluating SIJ pathology. Recall bias is an important component in patient-reported outcomes that has not been well studied in SIJ injection., Objective: The purpose of this study was to characterize the accuracy, direction, and magnitude of pain level recall bias following SIJ steroid injection and study the factors that affect patient recollection., Study Design: Prospective cohort study., Setting: Level 1 academic medical center., Methods: Using standardized questionnaires, baseline Numeric Rating Scale (NRS-11) scores were recorded for patients undergoing SIJ steroid injections at preinjection, at 4 hours postinjection, and at 24 hours postinjection. At a minimum of 2 weeks postinjection, patients were asked to recall their preinjection, 4-hour, and 24-hour postinjection NRS-11 scores. Actual and recalled NRS-11 scores were compared using paired t tests for each time interval. Multivariable linear regression was used to identify factors that correlated with consistent recall., Results: Sixty patients with a mean age of 66 years (65% women) were included. Compared to their preinjection pain score, patients showed considerable improvement at both 4 hours (mean difference [MD] = 3.28; 95% CI, 2.68 - 3.89), and 24 hours (MD = 3.23; 95% CI, 2.44 - 4.03) postinjection. Patient recollection of preinjection symptoms was more severe than actual (MD = 0.65; 95% CI, 0.31 - 0.99). Patient recollection of symptoms was also more severe than actual at 4 hours (MD = 0.50; 95% CI .04 - 1.04) as well as at 24 hours postinjection (MD = 0.80; 95% CI, 0.16 - 1.44). The magnitude of recall bias was mild and did not exceed the minimal clinically important difference. There was a moderate correlation between actual and recalled pain levels when comparing preinjection with the 4-hour postinjection NRS-11 score (correlation coefficient [r] =0.64; P < 0.001) and moderate correlation when comparing preinjection with the 24-hour postinjection NRS-11 score (r = 0.62; P < 0.001). Linear regression models showed that at preinjection, patients with a lower body mass index and the presence of coexisting psychiatric diagnoses were better at recalling their pain (P < 0.05). Patients with a higher body mass index also experienced less pain relief when comparing preinjection with the 4-hour postinjection NRS-11 score (P < 0.05)., Limitations: Recall pain scores were obtained via telephone surveys, which can lead to interview bias. One patient died, and 3 were lost to follow-up. We did not control for patient use of adjunctive pain relief modalities, which may modulate the overall response to injection. SIJ injections can also be diagnostic, so some patients may not have shared the same indication for injection or pain-generating diagnosis., Conclusions: Patients had favorable pain level responses to their SIJ steroid injection for both actual and recall surveys. Although patients demonstrated poor recall of absolute pain scores at preinjection, 4-hour postinjection, and 24-hour postinjection, they demonstrated robust recall of their net pain score improvement at both 4- and 24-hours postinjection. These findings suggest that there is utility in using patient recollection to describe the magnitude of pain relief following treatment for sacroiliac joint dysfunction.

Objectives: To validate self-reported occupational loud noise exposure against expert evaluation of noise levels in a French case–control study on acoustic neuroma and to estimate the impact of exposure misclassification on risk estimation. Methods: Noise levels were evaluated in 1006 jobs held by 111 cases and 217 population controls by an expert. Case–control differences in self-reporting were analyzed with logistic models. Sensitivity, specificity, positive and negative predictive values, and observed agreement of the self-reports were computed relative to the expert evaluation. They were used to calibrate the odds ratio (OR) between lifetime ever occupational loud noise exposure and the risk of acoustic neuroma, without adjustment for measurement error of the expert assessments. Results: Cases reported noise levels in individual jobs closer to the expert assessment than controls, but the case–control difference was small for lifetime exposures. For expert-rated exposure of 80 dB(A), reporting of individual jobs by cases was more sensitive (54% in cases, 37% in controls), whereas specificity (91% in cases, 93% in controls) and observed agreement (82% in cases, 81% in controls) were similar. When lifetime exposure was considered, sensitivity increased (76% in cases, 65% in controls), while cases specificity decreased (84%). When these values were used to calibrate self-reports for exposure misclassification compared to expert evaluation at 80 dB(A), the crude OR of 1.7 was reduced to 1.3. Conclusions: Despite the relatively accurate reporting of loud noise, the impact of the calibration on the OR was non-negligible. [ABSTRACT FROM AUTHOR]

The peak-end memory bias has been well documented for the retrospective evaluation of pain. It describes that the retrospective evaluation of pain is largely based on the discomfort experienced at the most intense point (peak) and at the end of the episode. This is notable because it means that longer episodes with a better ending can be remembered as less aversive than shorter ones; this is even if the former had the same peak in painfulness and an overall longer duration of pain. Until now, this bias has not been studied in the domain of anxiety despite the high relevance of variable levels of anxiety in the treatment of anxiety disorders. Therefore, we set out to replicate the original studies but with an induction of variable levels of anxiety. Of 64 women, half watched a clip from a horror movie which ended at the most frightening moment. The other half watched an extended version of this clip with a moderately frightening ending. Afterward, all participants were asked to rate the global anxiety which was elicited by the video. When the film ended at the most frightening moment, participants retrospectively reported more anxiety than participants who watched the extended version. This is the first study to document that the peak-end bias can be found in the domain of anxiety. These findings require replication and extension to a treatment context to evaluate its implications for exposure therapy. [ABSTRACT FROM AUTHOR]

Recall inaccuracies are a key limitation in a foodborne outbreak investigation. Misclassifications in self-reported exposure status reduce the power of epidemiological studies to detect meaningful associations between exposures and the development of illness. The purpose of this study was to investigate the effect of recall inaccuracies on the validity of food history data in a context comparable to outbreak investigations. The food consumption of 96 university students was collected using Ethica, a smartphone-based data acquisition system. Comprehensive food histories were captured for 10 days through a combination of digital images, meal descriptions, and short food exposure surveys. These real-time data were used as a reference to measure the sensitivity and specificity of food history questionnaires administered 7 or 18 days (2.5 weeks) after consumption (n = 86). The questionnaires and time intervals used in this study were designed to resemble a range of plausible local, provincial, and national enteric outbreak investigations conducted by public health officials in Canada. Comparably low accuracy of dietary memory after both time intervals suggests there is a substantial potential for bias for most food types following the first week after consumption. The magnitude of recall inaccuracies was not uniform across food types. This study serves as a first step in quantifying recall inaccuracies in a context comparable to how cases and controls might be questioned for outbreak investigations so that recall inaccuracies can be accounted for and mitigated in public health practice. Comparably low accuracy of dietary recall is present after 7 and 18 days. Experiencing gastrointestinal symptoms did not affect accuracy of dietary recall. Repeatedly recalling food exposures leads to a higher rate of false positives. Prevalence of exposure was associated with higher sensitivity and lower specificity. Recall inaccuracies can be quantified and accounted for in public health practice. [ABSTRACT FROM AUTHOR]

Alaa Althubaiti Department of Basic Medical Sciences, College of Medicine, King Saud bin Abdulaziz University for Health Sciences, Riyadh, Saudi Arabia Abstract: As with other fields, medical sciences are subject to different sources of bias. While understanding sources of bias is a key element for drawing valid conclusions, bias in health research continues to be a very sensitive issue that can affect the focus and outcome of investigations. Information bias, otherwise known as misclassification, is one of the most common sources of bias that affects the validity of health research. It originates from the approach that is utilized to obtain or confirm study measurements. This paper seeks to raise awareness of information bias in observational and experimental research study designs as well as to enrich discussions concerning bias problems. Specifying the types of bias can be essential to limit its effects and, the use of adjustment methods might serve to improve clinical evaluation and health care practice. Keywords: self-report bias, social desirability bias, recall bias, misclassification, measurement error bias, confirmation bias

Background: Childhood cancer is a rare but leading cause of morbidity and mortality. Established risk factors, accounting for <10% of incidence, have been identified primarily from case-control studies. However, recall, selection and other potential biases impact interpretations particularly, for modest associations. A consortium of pregnancy and birth cohorts (I4C) was established to utilise prospective, pre-diagnostic exposure assessments and biological samples.Methods: Eligibility criteria, follow-up methods and identification of paediatric cancer cases are described for cohorts currently participating or planning future participation. Also described are exposure assessments, harmonisation methods, biological samples potentially available for I4C research, the role of the I4C data and biospecimen coordinating centres and statistical approaches used in the pooled analyses.Results: Currently, six cohorts recruited over six decades (1950s-2000s) contribute data on 388 120 mother-child pairs. Nine new cohorts from seven countries are anticipated to contribute data on 627 500 additional projected mother-child pairs within 5 years. Harmonised data currently includes over 20 "core" variables, with notable variability in mother/child characteristics within and across cohorts, reflecting in part, secular changes in pregnancy and birth characteristics over the decades.Conclusions: The I4C is the first cohort consortium to have published findings on paediatric cancer using harmonised variables across six pregnancy/birth cohorts. Projected increases in sample size, expanding sources of exposure data (eg, linkages to environmental and administrative databases), incorporation of biological measures to clarify exposures and underlying molecular mechanisms and forthcoming joint efforts to complement case-control studies offer the potential for breakthroughs in paediatric cancer aetiologic research. [ABSTRACT FROM AUTHOR]

Several researchers have raised the concern that the cross-sectional association of retrospectively reported childhood adversity with self-reported onset of asthma and chronic bronchitis in adulthood may be confounded, as well as mediated by an individual's mental health. The aim of this study was to assess the effect of retrospectively reported childhood adversity on self-reported onset of asthma and chronic bronchitis in adulthood, independent of potential confounding and mediating variables (including respondent's mental health). We used data collected in 2007-2008 within the framework of the Tromsø Study (N = 12,981), a representative study of adult men and women in Norway. The associations of childhood adversity with asthma and chronic bronchitis were assessed with Poisson regression models. Relative risks (RR) and 95% confidence intervals (CI) were estimated with bias-corrected bootstrapping. Childhood adversity was associated with a 9% increased risk of asthma (RR = 1.09, 95% CI: 1.02, 1.16) and a 14% increased risk chronic bronchitis (RR = 1.14, 95% CI: 1.03, 1.26) in adulthood, independent of age, sex, parental history of psychiatric problems/asthma/dementia, education, smoking, social support, and respondent's mental health. Controlling for indicators of respondent's mental health reduced the strength of associations of childhood adversity with asthma and chronic bronchitis; however, the associations were still present in the same direction (p < .05). These findings suggest that the association of retrospectively reported childhood adversity with asthma and chronic bronchitis is independent of respondent's mental health. We recommend controlling for indicators of the respondent's mental health to assess an unbiased association of retrospectively measured childhood adversity with self-reported asthma and chronic bronchitis. [ABSTRACT FROM AUTHOR]

Objective Many researchers view retrospective reports with skepticism. Indeed, the observed association between retrospectively-reported childhood disadvantage (CD) and morbidity in adulthood has been criticized as an artefactual correlation driven by the psychological state of the respondent at the time of reporting (current psychological state). The aim of this study was to assess the role of current psychological state in the association between childhood disadvantage and morbidity in adulthood. Methods The present analysis used cross-sectional data collected in 2007–2008 within the framework of the Tromsø Study (N = 10,765), a representative study of adult men and women in Norway. The association between CD and the physical health outcomes heart attack, angina pectoris, chronic bronchitis/emphysema/COPD, diabetes mellitus, hypothyroid/low metabolism, migraine, hypertension, and comorbidity (i.e., the sum of these physical health outcomes) was assessed with Poisson regression models. Relative risks (RR) and 95% confidence intervals (CI) were estimated. A wide range of indicators of respondents’ current psychological state were included in the models to assess the % attenuation in estimates. Results CD was associated with an increased risk of heart attack, angina pectoris, chronic bronchitis/emphysema/COPD, diabetes mellitus, hypothyroid/low metabolism, migraine, hypertension, and comorbidity (p < 0.05), independent of respondents' current psychological state. A sizeable proportion (23–42%) of the association between CD and physical health outcomes was driven by recall bias or mediation via respondents’ current psychological state. Controlling for indicators of current psychological state reduced the strength of associations between CD and physical health outcomes; however, the independent associations remained in the same direction. Conclusion The association between retrospectively-reported CD and physical health outcomes in adulthood is not driven entirely by respondent's current psychological state. [ABSTRACT FROM AUTHOR]