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This article refutes a recent claim that computer-based tests produce biased scores for very proficient test takers who make mistakes on one or two initial items and that the ‘‘bias’’ can be reduced by using a four-parameter IRT model. Because the same effect occurs with pattern scores on nonadaptive tests, the effect results from IRT scoring, not from adaptive testing. Because very proficient test takers rarely err on items of middle difficulty, the so-called bias is one of selective data analysis. Furthermore, the apparently large score penalty for one error on an otherwise perfect response pattern is shown to result from the relative stretching of the IRT scale at very high and very low proficiencies. The recommended use of a four-parameter IRT model is shown to have drawbacks.

One of the articles contained within European Council Directive 86/609/EEC states that “Persons who carry out experiments or take part in them, and persons who take care of animals used for experiments, including duties of a supervisory nature, shall have appropriate training”. In effect, this article stipulates that only competent individuals are allowed to work with laboratory animals. At least three groups of individuals can be identified with different responsibilities toward experimental animals: animal technicians, scientists, and veterinarians/animal welfare officers. The responsibilities and duties of the individuals within each of these categories differ. This paper focuses on the training of scientists. The scientist designs, and often also performs, animal experiments. Therefore, scientists must be educated to develop an attitude of respect toward laboratory animals, and must be trained so that, if an experiment must be performed with animals, it is designed according to the highest possible scientific and ethical standards. In The Netherlands, the law stipulates that scientists intending to work with animals must have completed a course in laboratory animal science. This compulsory course started in 1986. The Department of Laboratory Animal Science at Utrecht University is responsible for the national coordination of this course. Participants must have an academic degree (at the level of MSc) in one of the biomedical sciences, such as biology, medicine or veterinary medicine. Although the course is an intensive 3-week, 120-hour long course, which covers both technical and ethical aspects of laboratory animal experimentation, it cannot provide full competence. It is designed to provide sufficient basic training and knowledge to enable students to design animal experiments, and to develop an attitude that will be conducive to the implementation of the Three Rs. However, full competence will always require further training that can only be acquired as a result of practical experience gained while working in the field of laboratory animal research. Evaluations subsequent to the course have revealed that more than 98% of the students regard the course as indispensable for all scientists working in a research area where animal experiments are performed. They agree that the course not only contributes to the quality of experiments and to the welfare of animals, but also to a decrease in the number of animals used in experiments.

To assess the effect of procedures on animal welfare, various physiological parameters, such as body weight, hormone levels in plasma and/or urine, heart rate (HR), blood pressure and body temperature (BT), can be used. When measuring physiological parameters with techniques involving restraint of the animals, the results must be interpreted with caution, since restraint itself may have an effect on those parameters. Radio-telemetry, using an implantable transmitter, provides a way to obtain more accurate and reliable physiological measurements from freely moving animals in their own environment. In this study, we have used radio-telemetry to investigate the influence of conditioning on the increase of HR and BT as provoked by handling of mice. It was found that, after a conditioning period of 12 days, the increase of HR due to handling was significantly reduced.

The Third World Congress (1999, Bologna) celebrated the fortieth anniversary of the publication of Russell & Burch's The Principles of Humane Experimental Technique. There was the general notion that the Three Rs offer a unifying concept that contributes to a progressive reduction and refinement in animal use without compromising the quality of research, human health or the protection of the environment. The Bologna Three Rs Declaration was accepted unanimously, calling upon all parties involved to incorporate the Three Rs into animal-based research. The question is raised, what progress has been made and, in particular, what are the developments in animal use and in the implementation of validated alternative methods. For the present contribution, we requested colleagues from European countries, Canada and the United States to provide information on the numbers of animals currently used for scientific purposes, on the development and implementation of alternative methods and on future perspectives about the issues. Based on the results of this survey, the conclusion is reached that legislative regulations are widely implemented and have become rather strict during the last decade. An exception here is the legislative regulation for rats, mice and birds in the USA. These species are not (yet) protected by the US Animal Welfare Act. The number of animals used has decreased considerably, and the review of protocols by animal ethics committees has become a significant trend. In all countries, there is growing support for the Three Rs concept.

This study examines the validity of measures of socioeconomic status (SES) as reported by adolescents. Adolescents completed a self-administered questionnaire that included eight measures of SES. Mothers also reported on selected measures of SES. Supporting criterion validity, adolescents and mothers had relatively high agreement on the SES measures. Older adolescents, those less involved in risk behaviors, and those who do better in school gave more accurate SES reports and/or were less likely to have missing SES data. Those in households without fathers were less likely to know fathers’ information. Income was not asked of the adolescents. However, most adolescent-reported SES questions varied systematically and in the expected direction with mothers’income report. In terms of construct validity, the SES measures related to adolescent health measures in the predicted way—that is, those with higher SES were more likely to report better physical and emotional health.

Four groups of mice of the same inbred strain, but with different transgenic backgrounds (no treatment; integration of a functional corticotrophin-releasing factor [CRF] gene construct; integration of a non-functional CRF gene construct; transgenic technique without integration of a DNA construct) were compared, in order to identify and quantify indicators of discomfort in transgenic animals. This approach enables us to differentiate between the effects of the technique of transgenesis and the effects caused by the expression of the transgene. This paper emphasises the search for differences in the early post-natal development of the animals. To this end, newborn mice have been subjected to various behavioural tests; moreover, their growth and morphological characteristics were measured from birth up to the age of 3 weeks. The results indicate that the presence of the microinjected DNA-construct influences the survival rate during the first 2–3 days after birth. The average loss of pups was about 10%, in contrast to the groups without the DNA construct, in which none of the pups died. The increase in the relative body weight of pups with a functional CRF construct was significantly lower than in the other groups, but only during the first 11 days. No significant differences in morphological characteristics or behavioural development were observed between the four groups. This approach was found to be adequate for detecting a broad variety of behavioural and morphological characteristics. Before general conclusions about the extent to which the technique of transgenesis affects animal welfare can be drawn, more transgenic lines should be studied in this way.

This study examined the effects of computer pre sentation on speeded clerical tests. Two ratio scores— average number of correct responses per minute and its inverse, average number of seconds per correct re sponse—were examined as variants of the conven tional score, number of correct responses in a fixed in terval of time. Ratio scores were more reliable than number-correct scores and were less sensitive to test ing time. Tests administered on the computer were found to be at least as reliable as conventionally ad ministered tests, but examinees were much faster in the computer mode. Correlations between paper-and- pencil and computer modes were high, except when task differences were introduced by computer imple mentation.

This study examined some effects of using a unidi mensional IRT model when the assumption of unidi mensionality was violated. Adaptive and nonadaptive tests were formed from two-dimensional item sets. The tests were administered to simulated examinee populations with different correlations of the two un derlying abilities. Scores from the adaptive tests tended to be related to one or the other ability rather than to a composite. Similar but less disparate results were obtained with IRT scoring of nonadaptive tests, whereas the conventional standardized number-correct score was equally related to both abilities. Differences in item selection from the adaptive administration and in item parameter estimation were also examined and related to differences in ability estimation. Index terms: ability estimation, adaptive testing, item pa rameter estimation, item response theory, multidimen sionality.