A survey of student assessment in U.S. medical schools: the balance of breadth versus fidelity.

BACKGROUND: Faced with the challenge to develop models of assessment relevant to work of physicians, medical schools have broadened their assessment of medical student competency. PURPOSE: U.S. medical schools were surveyed to determine the extent to which student assessments have broadened beyond multiple-choice question (MCQ) examinations and preceptor ratings. METHODS: A survey mailed to 126 accredited U.S. medical schools asked respondents to indicate the frequency with which a variety of assessment methods were used in each year of the curriculum. RESULTS: Examinations dominated preclinical assessments. Year 3 relied heavily on faculty ratings, live observations, and MCQs. Preceptor ratings were used most in year 4. CONCLUSIONS: A variety of competency assessments currently are used; MCQs remain a core assessment method. Year 3 had the greatest breadth of assessment strategies. The findings suggest that educators continue to be challenged to balance the breadth of competencies sampled with the fidelity of the assessment experience.

The genetic architecture of divergence between threespine stickleback species.

The genetic and molecular basis of morphological evolution is poorly understood, particularly in vertebrates. Genetic studies of the differences between naturally occurring vertebrate species have been limited by the expense and difficulty of raising large numbers of animals and the absence of molecular linkage maps for all but a handful of laboratory and domesticated animals. We have developed a genome-wide linkage map for the three-spined stickleback (Gasterosteus aculeatus), an extensively studied teleost fish that has undergone rapid divergence and speciation since the melting of glaciers 15,000 years ago. Here we use this map to analyse the genetic basis of recently evolved changes in skeletal armour and feeding morphologies seen in the benthic and limnetic stickleback species from Priest Lake, British Columbia. Substantial alterations in spine length, armour plate number, and gill raker number are controlled by genetic factors that map to independent chromosome regions. Further study of these regions will help to define the number and type of genetic changes that underlie morphological diversification during vertebrate evolution.

The prevalence and symptoms of migraine in a consecutive series of patients attending an optometric practice.

The purpose of the investigation was to determine the prevalence of migraine in optometric practice and to document the variety of presentation. One thousand consecutively presenting patients of a suburban optometric practice were asked questions to establish whether they experience migraine or have experienced it in the past. Those with a history of migraine were asked further questions to establish the type of migraine and to document the variety of the symptoms they experienced. Eleven percent of male and 23% of female patients currently had migraine or had experienced it in the past. When corrected for the age distribution of the population of the state from which the sample was drawn, it is estimated that the general population prevalence of migraine is 9.5% for men and 19.7% for women. Half of the sample of migraineurs had not experienced a migraine within the last 12 months. A third had a known family history of migraine. Nearly half had not had a formal medical diagnosis of their migraine but only 7 had attended for optometric examination because of their migraine symptoms. Four of these patients had single migraine-like episodes and three had migraine equivalents (acephalic migraine, experiencing the visual aura without headache). Optometrists must be thoroughly familiar with migraine and its varied presentation because of its high prevalence, the explanatory value in offering a formal diagnosis of migraine, and the risk that headache or visual aura may be wrongly ascribed to migraine when there is some more sinister cause of the symptoms.

Can clinical colour vision tests be used to predict the results of the Farnsworth lantern test?

Clinicians usually do not have access to a lantern test when making an occupational assessment of the ability of a person with defective colour vision to recognise signal light colours: they must rely on the results of ordinary clinical tests. While all colour vision defectives fail the Holmes Wright Type B lantern test and most fail the Holmes Wright Type A lantern, 35% of colour vision defectives pass the Farnsworth lantern. Can clinical tests predict who will pass and fail the Farnsworth lantern? We find that a pass (less than two or more diametrical crossings) at the Farnsworth Panel D 15 Dichotomous test has a sensitivity of 0.67 and specificity of 0.94 in predicting a pass or fail at the Farnsworth lantern test: a Nagel range of > 10 has a sensitivity of 0.87 and a specificity of 0.57. We conclude that neither the D 15 nor the Nagel Anomaloscope matching range are satisfactory predictors of performance on the Farnsworth Lantern.

A critique of the usefulness of inferential statistics in applied behavior analysis.

Researchers continue to recommend that applied behavior analysts use inferential statistics in making decisions about effects of independent variables on dependent variables. In many other approaches to behavioral science, inferential statistics are the primary means for deciding the importance of effects. Several possible uses of inferential statistics are considered. Rather than being an objective means for making decisions about effects, as is often claimed, inferential statistics are shown to be subjective. It is argued that the use of inferential statistics adds nothing to the complex and admittedly subjective nonstatistical methods that are often employed in applied behavior analysis. Attacks on inferential statistics that are being made, perhaps with increasing frequency, by those who are not behavior analysts, are discussed. These attackers are calling for banning the use of inferential statistics in research publications and commonly recommend that behavioral scientists should switch to using statistics aimed at interval estimation or the method of confidence intervals. Interval estimation is shown to be contrary to the fundamental assumption of behavior analysis that only individuals behave. It is recommended that authors who wish to publish the results of inferential statistics be asked to justify them as a means for helping us to identify any ways in which they may be useful.

Action on worksite health and safety problems: a follow-up survey of workers participating in a hazardous waste worker training program.

In it's worker health and safety training program, the California-Arizona Consortium aims to promote worker action to improve health and safety conditions. To assess action on worker-identified health and safety problems, 278 trainees were interviewed 3-8 months after training. Associations with three outcomes were analyzed: (1) attempted action, (2) problem correction, and (3) trainee participation. Perceived management support was associated with all three outcomes, pointing to its key role in maximizing the impact of training. Odds of attempted action were 2-5 times greater with support than without. Trainees for whom English was not the primary language (mostly Spanish speakers) attempted action as often as English speakers. However, the odds of their correcting problems were half that of the English-speaking workers. It is suggested this was due to a perceived lack of control over organizational resources for change, not simply due to communication barriers.

Effect of VDUs on the eyes: report of a 6-year epidemiological study.

One thousand, three hundred and sixteen office workers [692 visual display unit (VDU) users, 624 controls in the first year] were examined once each year over a 6-year period to establish whether or not VDU work was a factor in the occurrence of visual symptoms, ocular abnormalities, or ocular disease. Statistical analysis showed that although there were differences between VDU users and nonusers in the amount of myopia, the prevalence of some symptoms, and the prevalence of signs of fundal or vitreal disease, the differences were small and there were no clear trends or patterns to lend convincing support to the hypothesis that VDU work may be a risk factor. There were no significant differences in the prevalence and incidence of cataract.

HIV-related knowledge and attitudes among medical students in China.

A modified version of the 'WHO/KABP Questionnaire for Students' was administered to 302 students at a medical university in China. The instrument included items to assess the students' demographic background, knowledge of AIDS/HIV, attitudes about AIDS, as well as towards people infected with HIV, those groups commonly labelled as 'high risk' and toward sources of information. The average score on the knowledge scale was 80% correct. There was a substantial disparity in knowledge between how HIV is transmitted and how HIV is not transmitted--90% of the former items were answered correctly, while only 72% of the latter were answered correctly. Over 40% of the sample blamed prostitutes for AIDS in China, whereas 22% blamed drug addicts and 6% blamed homosexuals. Two-thirds of the sample indicated that they thought people with AIDS got what they deserve. About one-third of the sample supported quarantine measures as well as keeping infected students out of classrooms. Nearly half of the sample indicated that they did not trust any of the official sources of health information we asked about and 27% said that they thought the government was concealing information about AIDS.

PIP: A modified version of the WHO/KAP Questionnaire for Students was administered to 302 students at a medical university in China to assess their demographic background, knowledge of AIDS/HIV, attitudes about AIDS, and attitudes toward people infected with HIV. 90% responded correctly about how HIV is transmitted, but only 72% responded correctly to questions on how HIV is not transmitted; the average score on the knowledge scale was 80% correct. With regard to infected individuals in commonly considered high-risk groups, more than 40% blamed prostitutes for AIDS in China, 22% blamed drug addicts, and 6% blamed homosexuals. Two-thirds indicated that they thought people with AIDS got what they deserved; one-third supported quarantine measures as well as keeping infected students out of the classrooms; and almost 50% indicated that they did not trust any of the official sources of health information about which they were asked. 27% said that they thought the government was concealing information about AIDS.

What do color vision defectives say about everyday tasks?

A lengthy questionnaire was administered to 102 people with defective color vision and to an equal number of people with normal color vision. The questionnaire asked about the subjects' awareness of their defect and their knowledge of defective color vision as well as exploring the difficulties they experience with color at work and in pursuing leisure activities. The questionnaire was administered in the consulting room under conditions that might be expected to elicit frank replies. Nearly 90% of dichromats and up to two-thirds of anomalous trichomats reported difficulties with everyday tasks that involve color, nearly one-half of the dichromats and one in five anomalous trichromats reported difficulty with traffic lights, and similar proportions reported color difficulties in their present jobs. Substantial numbers reported that their color vision defect had affected their choice of career and many had been excluded from a chosen occupation. The screening of color vision in schools and provision of appropriate career counselling is urged.

Are colour vision standards justified for the transport industry?

Colour vision standards are imposed in the road, rail, maritime and aviation industries and are often subject to vigorous opposition by those excluded by the standard. With greater emphasis in recent years on equality of opportunity, it is important that standards of personal fitness, such as colour vision standards, be subject to critical scrutiny. Such appraisal should be able to demonstrate that the community benefit arising from the application of the standard is sufficient to justify the personal and other costs of retaining the standard. This paper reviews the evidence relating to colour vision standards in the transport industries and concludes that a strong case can be made for their retention in public transport.

Defective colour vision can impede information acquisition from redundantly colour-coded video displays.

Earlier findings showed that redundant colour coding decreased response times and reduced errors in carrying out various tasks that required information acquisition from the video display of an electronic flight instrument system. The results of this experiment showed that observers with defective colour vision have slower response times and higher error rates than normal observers for some of the tasks and that their performance is similar to that of colour-normal observers for a monochrome display. However, they were not disadvantaged when blue was used to colour code the target feature. Protanopes were shown to be especially disadvantaged in responding to a red 'fail' message.

Assessment of contrast sensitivity of patients with macular disease using reduced contrast near visual acuity charts.

A set of near Bailey-Lovie logMAR letter charts that varied in contrast from 0.40 dB (C = 0.95) to 58.0 dB (C = 0.001) were used to measure the middle and high spatial frequency range of the contrast sensitivity function (CSF) of 15 subjects with age-related maculopathy (ARM) and 15 age-matched normal subjects. The letter charts were shown to have good test-retest reliability. Compared with measures made using CRT generated square wave gratings of variable contrast and spatial frequency they were also shown to provide a valid measure of CSF in the mid to high spatial frequency range. The 20.0 dB letter chart alone was shown to be a good screening device for macular disease. The letter charts do not provide a measure of the peak of the CSF and a supplementary test of contrast sensitivity is needed to quantify contrast sensitivity at a low spatial frequency. Three measures are proposed as necessary to document foveal visual capability of patients with macular disease: distance logMAR visual acuity to measure high spatial frequency resolution, visual acuity with letter charts of 20 dB contrast to assess mid spatial frequency resolution; and contrast sensitivity for the detection of an edge to estimate contrast sensitivity for larger objects.

Reliability and validity of simple photographic plate tests of contrast sensitivity.

Sets of edge and square wave grating photographic plates of varying contrasts were used to measure the mid to low spatial frequency range of the contrast sensitivity function (CSF) of 20 subjects with evident ocular disease and 20 age-matched normal subjects. Both plate tests were shown to have good test-retest reliability and to correlate well with electronic cathode ray tube (CRT) measures of CSF. The edge test, when administered in 2-dB steps of ascending contrast, has optimum sensitivity of 0.70 and specificity of 0.84 for detecting the patient with ocular disease with a fail criterion of less than 38 dB. A measure of edge contrast sensitivity was also shown to be a good predictor of the peak of the CSF, which is shown to be largely independent of the visual acuity of the subject. The 2 c/deg and 4 c/deg plates did not provide more information about the visual difficulties of subjects than the edge test. We advocate the use of an edge test as a simple clinical measure of low spatial frequency contrast sensitivity that provides information about visual dysfunction not provided by a measure of visual acuity.

Origins of colour vision standards within the transport industry.

Colour vision standards should reflect changes in our understanding of the nature of these defects as well as technological advances that place less importance upon the visual senses of the human operator. Therefore it is suggested that visual standards be subject to routine reviews in order to assess their suitability for modern work environments. This paper gives a chronological account of the introduction of colour vision standards by several national transport authorities and identifies historical reasons that led to their implementation. It is concluded that the same factors that gave rise to the adoption of early colour vision standards are still relevant for modern transport systems. However the recent deployment of automatic or semi-automatic control or navigational systems has substantially altered man's role from being the primary source of information input to one of a monitoring process. This has generated a good deal of debate and uncertainty regarding the level of responsibility that a human operator has for the control of modern transport vehicles. Nevertheless, it is argued that in the absence of complete automation some type of visual standard is needed whenever visual judgements must be made by human observers.

The effect of variability of background elements on the conspicuity of objects.

The effect of complex backgrounds on target visibility was studied by asking observers to locate a disc target presented on a background of randomly arranged discs. A previous paper (Vision Res. 22, 1241-1252, 1982) explored the effect of increasing the density (numerosity) of the background elements when the elements were all the same size and luminance. In this investigation the size or the luminance of the background elements varied although mean size and mean luminance was held constant. Variability of the size of the background elements had a substantial effect on the size contrast necessary to detect the target. The data are well described by a contrast metric CT which assumes that observers detect the target by comparing it to a weighted average of the larger elements. The larger elements that determine the weighted average are those that all appear the same size because, at the eccentricity of target, the observers are unable to distinguish their differences in size. The threshold values of CT for detection of the target at a given level of probability were dependent on eccentricity but independent of the degree of variability of the background elements. The threshold contrast was also the same as the necessary for the more elementary task of discriminating size differences of two discs. In a second experiment it is shown that variability in the luminance of the background elements did not affect target visibility. This result is explained by reference to the data in our earlier paper from which it can be shown that the observers were unable to perceive the differences in luminance in their peripheral visual field so that, within limits, backgrounds that vary in luminance can be validly characterised by mean luminance.