Differences In Mean Test Scores Research Articles

A Novel Digital Digit-Symbol Substitution Test Measuring Processing Speed in Adults At Risk for Alzheimer Disease: Validation Study

Assessing cognitive constructs affected by Alzheimer disease, such as processing speed (PS), is important to screen for potential disease and allow for early detection. Digital PS assessments have been developed to provide widespread, efficient cognitive testing, but all have been validated only based on the correlation between test scores. Best statistical practices dictate that concurrent validity should be assessed for agreement or equivalence rather than using correlation alone. This study aimed to assess the concurrent validity of a novel digital PS assessment against a gold-standard measure of PS. Adults aged 45-75 years (n=191) participated in this study. Participants completed the novel digital digit-symbol substitution test (DDSST) and the Repeatable Battery for the Assessment of Neuropsychological Status coding test (RBANS-C). The correlation between the test scores was determined using a Pearson product-moment correlation, and a difference in mean test scores between tests was checked for using a 2-tailed dependent samples t test. Data were analyzed for agreement between the 2 tests using Bland-Altman limits of agreement and equivalency using a two one-sided t tests (TOST) approach. A significant moderate, positive correlation was found between DDSST and RBANS-C scores (r=.577; P<.001), and no difference in mean scores was detected between the tests (P=.93). Bias was nearly zero (0.04). Scores between the tests were found to display adequate agreement with 90% of score differences falling between -22.66 and 22.75 (90% limits of agreement=-22.91 to 22.99), and the scores were equivalent (P=.049). Analyses indicate that the DDSST is a valid digital assessment of PS. The DDSST appears to be a suitable option for widespread, immediate, and efficient PS testing. ClinicalTrials.gov NCT04559789; https://clinicaltrials.gov/ct2/show/NCT04559789.

Measuring the Impact of a Pharmacist-Driven Blood Factor Education Program: A Prospective, Single-Center Observational Study.

Introduction: Patients with bleeding disorders are best served by multidisciplinary teams. Pharmacists can play a critical role in the optimal management of patients with bleeding disorders through blood factor stewardship strategies and programs. An educational program was developed and implemented wherein a hematology pharmacist provided brief recorded lectures to an entire department of pharmacists in a multi-site health-system with the goal to improve the knowledge base and confidence among this population of general practitioners. Methods: The primary objective of this study was to evaluate the educational outcomes of a blood factor education program for pharmacists. The impact of the educational program was determined by measuring the difference in mean test scores between the pre- and post-program surveys. Results: The final analysis included 214 participants. The primary endpoint of mean competency test score was significantly improved in the post-test compared to pre-test (78.33% vs 52.83%; P < .0001). Any degree of test score improvement was observed in 99% (n = 212) of participants. Pharmacist confidence was significantly improved in all 20 domains of bleeding disorders and blood factor product verification and management. Conclusion: This program identified that most pharmacists in a large multi-site health-system were not familiar with bleeding disorders to a satisfactory degree, commonly because of the relative rare encounters with bleeding disorder-related orders, and that despite systems-based support there was an opportunity to improve practice through education. Such educational programming could be beneficial for the development of pharmacist-provided care and is a measure that could be implemented as part of blood factor stewardship initiatives.

School performance in Danish children exposed to maternal type 1 diabetes in utero: A nationwide retrospective cohort study.

Conflicting results have been reported concerning possible adverse effects on the cognitive function of offspring of mothers with type 1 diabetes (O-mT1D). Previous studies have included offspring of parents from the background population (O-BP), but not offspring of fathers with type 1 diabetes (O-fT1D) as the unexposed reference group. This is a population-based retrospective cohort study from 2010 to 2016. Nationally standardized school test scores (range, 1 to 100) were obtained for public school grades 2, 3, 4, 6, and 8 in O-mT1D and compared with those in O-fT1D and O-BP. Of the 622,073 included children, 2,144 were O-mT1D, and 3,474 were O-fT1D. Multiple linear regression models were used to compare outcomes, including the covariates offspring with type 1 diabetes, parity, number of siblings, offspring sex, smoking during pregnancy, parental age, and socioeconomic factors. Mean test scores were 54.2 (standard deviation, SD 24.8) in O-mT1D, 54.4 (SD 24.8) in O-fT1D, and 56.4 (SD 24.7) in O-BP. In adjusted analyses, the mean differences in test scores were -1.59 (95% CI -2.48 to -0.71, p < 0.001) between O-mT1D and O-BP and -0.78 (95% CI -1.48 to -0.08, p = 0.03) between O-fT1D and O-BP. No significant difference in the adjusted mean test scores was found between O-mT1D and O-fT1D (p = 0.16). The study's limitation was no access to measures of glycemic control during pregnancy. O-mT1D achieved lower test scores than O-BP but similar test scores compared with O-fT1D. Glycemic control during pregnancy is essential to prevent various adverse pregnancy outcomes in women with type 1 diabetes. However, the present study reduces previous concerns regarding adverse effects of in utero hyperglycemia on offspring cognitive function.

A Consideration of Racism in Pediatric Epidemiologic Studies

A Consideration of Racism in Pediatric Epidemiologic Studies

An Investigation of the Impact of a Flipped Classroom Instructional Approach on High School Students’ Content Knowledge and Attitude Toward the Learning Environment.

The idea of the “flipped classroom” has become increasingly popular in education. However, very little research in how “flipped classrooms” impact high school students’ ability to perform on exams has been done. The purpose of this research is to add to the body of knowledge and help provide data to investigate how well students learn physics content by using the flipped classroom in a high school Physics with Technology class.&#x0D; Seven periods of Physics with Technology at Lone Peak High School in Highland, UT were used in this study. Three of the classes were randomly assigned to be “flipped” while the other four were taught using what is considered a “traditional” method of instruction of physics (guided inquiry). The pacing and content was matched each day and all classes participated in the same labs, homework, quizzes and tests. The defining difference is the method which the content was covered. The flipped classes watched video lectures at home to learn the majority of the content, then did what is traditionally known as “homework” in class with the teacher present to help.&#x0D; In this study, it was found that there was no statistically or practically significant difference in mean test scores for the first three units. Student responses on a survey also showed very little statistical difference in the students’ attitudes towards the classroom environment in either instructional method.

P.069 Pediatric neurology subspecialty education development in a resource limited setting

Background: In 2013, the University of Calgary (UofC) - Mbarara University of Science and Technology (MUST) Pediatric Education Program was established when the Pediatric Department in Mbarara, Uganda identified a need for enhanced education in pediatric subspecialty areas. We report on the experience of developing the pediatric neurology subspecialty curriculum. Methods: Pre-visit meetings established mutually agreed upon objectives and learning activities that were implemented over 2-week periods in 2015 and 2018. Pre and post-tests were administered to MUST Pediatric residents. Mean differences in test scores were compared using a Student t-test. Residents provided written feedback following the end of the second visit. Results: A pediatric neurologist (AM) visited MUST (2015 and 2018) to deliver the curriculum. The second visit was accompanied by a senior UofC Pediatrics resident (LD). Eight and 14 residents at MUST participated in the curriculum in 2015 and 2018, respectively. Neurology test scores improved in 2015 from a mean of 43% to 61% (p = 0.011) and in 2018 from 53% to 84% (p &amp;lt; 0.00001). Teaching sessions were well received by MUST residents. Conclusions: Collaboration between UofC faculty and MUST established an effective pediatric neurology curriculum that was well-received by residents.

Impact of immediate feedback on the learning of medical students in pharmacology

Introduction:Providing feedback to students is an essential component in medical education and has been shown to improve the students’ learning. The purpose of this study is to evaluate the effect of computer-based immediate feedback on the medical students’ learning in a pharmacology course. Methods:In this prospective intervention study some feedback modules in pharmacology (FMP) were prepared in two topics: the cardiovascular system (CVS) and chemotherapy, using blank templates on “Hot Potatoes” software. The FMP included MC-based questions and two versions were developed: one with feedback (FMP-1) and the other without feedback (FMP-2). The FMP-1 module provided immediate feedback for each option the student chose. The students (n=48) were randomized by computer generated random number table to two groups A and B to receive the module in CVS, i.e., FMP-1 and FMP-2, respectively. A cross-over design was adopted to expose all students to immediate feedback modules. The test scores were compared and feedback was obtained from students and faculty using a validated questionnaire. A focus group discussion was conducted to clarify the issues raised by the students. Results: The module with immediate feedback was much better appreciated by the students than the module without feedback. The students spent more time on FMP-1 (42±7.00 minutes vs 27±12.36 minutes; p<0.001 in chemotherapy and 40±12.11 minutes vs 24±6.01 minutes; p<0.001 in CVS). However, there was no statistically significant difference in mean test scores. The qualitative data collected provided important information on the value of immediate feedback. The students believed that immediate feedback was an excellent way for self-assessment and improved their deeper understanding of content areas. They also felt that it supplemented their traditional learning habits and stimulated them to read more. The students enjoyed its non-threatening nature. Conclusion:Immediate feedback improved the deeper understanding of pharmacology and its relevance to medicine for the two topics although immediate feedback did not improve test scores. Overall, immediate feedback had a positive impact on the students’ self-directed learning.

Effects of an Online Educational Module on School Nurses' Knowledge of HPV Vaccination.

Results of a previous state-wide survey revealed generally low knowledge levels about HPV vaccination among school nurses in Missouri. A short, online educational module targeted to address the specific low-scoring items was then created. All 440 lead school nurses in Missouri were invited by e-mail to participate in an online HPV educational module and study. The e-mail contained a link to the module that included a consent form, a test, and a downloadable completion certificate. The test consisted of 12 multiple choice and true-or-false items based directly on the content contained in the module. An independent samples t test was used to determine pre-post differences in mean test scores. Scores improved significantly (p < .05) pre-post intervention; however, surveillance or epidemiology-related questions were still commonly missed. Using brief, targeted, online trainings to improve knowledge of specific health-related content may be a practical option for busy school nurses. J Contin Educ Nurs. 2017;48(9):431-436.

Is there inter-procedural transfer of skills in intraocular surgery? A randomized controlled trial.

To investigate how experience in simulated cataract surgery impacts and transfers to the learning curves for novices in vitreoretinal surgery. Twelve ophthalmology residents without previous experience in intraocular surgery were randomized to (1) intensive training in cataract surgery on a virtual-reality simulator until passing a test with predefined validity evidence (cataract trainees) or to (2) no cataract surgery training (novices). Possible skill transfer was assessed using a test consisting of all 11 vitreoretinal modules on the EyeSi virtual-reality simulator. All participants repeated the test of vitreoretinal surgical skills until their performance curve plateaued. Three experienced vitreoretinal surgeons also performed the test to establish validity evidence. Analysis with independent samples t-tests was performed. The vitreoretinal test on the EyeSi simulator demonstrated evidence of validity, given statistically significant differences in mean test scores for the first repetition; experienced surgeons scored higher than novices (p=0.023) and cataract trainees (p=0.003). Internal consistency for the 11 modules of the test was acceptable (Cronbach's α=0.73). Our findings did not indicate a transfer effect with no significant differences found between cataract trainees and novices in their starting scores (mean±SD 381±129 points versus 455±82 points, p=0.262), time to reach maximum performance level (10.7±3.0hr versus 8.7±2.8hr, p=0.265), or maximum scores (785±162 points versus 805±73 points, p=0.791). Pretraining in cataract surgery did not demonstrate any measurable effect on vitreoretinal procedural performance. The results of this study indicate that we should not anticipate extensive transfer of surgical skills when planning training programmes in intraocular surgery.

Use of an e-Learning Educational Module to Better Equip Doctors to Prescribe for Older Patients: A Randomised Controlled Trial.

The older patient population is significantly different from the younger adult population with regards to dose selection for a wide variety of drugs. Recent investigation of prescribing attitudes indicates that doctors feel there is insufficient distinction made between the two cohorts during their undergraduate education, and that doctors do not receive enough training in geriatric pharmacotherapy. The aim of this study was to determine if an online module, focused on geriatric pharmacotherapy, improves doctors' prescribing knowledge, as well as prescribing confidence, as applied to older patients. The impact of an online educational module (SCRIPT) on hospital doctors' prescribing knowledge and confidence with regards to older patients was assessed by randomised controlled trial. Control and intervention groups completed assessments at baseline, 4 and 12weeks. Primary outcome was difference in mean test scores. Student's t tests were used to analyse the data. Qualitative data on participant's confidence levels were also collected. Eighty participants completed the 12-week trial. The SCRIPT intervention resulted in a 22% difference in mean test scores between control and intervention groups at 4weeks (23.12 marks versus 33.67 marks; p<0.0001; 95% CI 8.13-12.97). This significance was maintained at 12weeks. Thirty-four percent of participants in the intervention group rated themselves as 'confident' with regards to prescribing for older patients post-intervention compared with 12% in the control group. A short e-learning module focused on geriatric pharmacotherapy can significantly improve doctors' prescribing knowledge and confidence with regards to older patients. Clinicaltrials.gov NCT02405975.

Impact of virtual microscopy with conventional microscopy on student learning in dental histology.

In dental histology, the assimilation of histological features of different dental hard and soft tissues is done by conventional microscopy. This traditional method of learning prevents the students from screening the entire slide and change of magnification. To address these drawbacks, modification in conventional microscopy has evolved and become motivation for changing the learning tool. Virtual microscopy is the technique in which there is complete digitization of the microscopic glass slide, which can be analyzed on a computer. This research is designed to evaluate the effectiveness of virtual microscopy with conventional microscopy on student learning in dental histology. A cohort of 105 students were included and randomized into three groups: A, B, and C. Group A students studied the microscopic features of oral histologic lesions by conventional microscopy, Group B by virtual microscopy, and Group C by both conventional and virtual microscopy. The students' understanding of the subject was evaluated by a prepared questionnaire. The effectiveness of the study designs on knowledge gains and satisfaction levels was assessed by statistical assessment of differences in mean test scores. The difference in score between Groups A, B, and C at pre- and post-test was highly significant. This enhanced understanding of the subject may be due to benefits of using virtual microscopy in teaching histology. The augmentation of conventional microscopy with virtual microscopy shows enhancement of the understanding of the subject as compared to the use of conventional microscopy and virtual microscopy alone.

Correcting for prematurity affects developmental test scores in infants born late and moderately preterm

BackgroundCorrected age is typically applied when assessing the development of children born <32weeks of gestation. There is no consensus as to whether corrected age should be applied when assessing children born late/moderately preterm (LMPT; 32–36weeks of gestation). AimsThis study explored the impact of corrected age on developmental test scores in infants born LMPT. Study design221 LMPT infants were assessed at two years corrected age using the Bayley-III cognitive and language scales, from which cognitive and language composite scores were derived (Normative Mean 100; SD 15). Assessments were then re-scored using chronological age. Bayley-III composite scores <80 were used to define developmental delay. Paired sample t-tests were used to assess the difference in mean test scores derived using corrected versus chronological age, and McNemar's tests to assess the difference in the proportion of infants with developmental delay using corrected versus chronological age. ResultsMean corrected age scores were significantly higher than chronological age scores (cognitive: 2.1 points; 95% CI 1.6, 2.5; language 2.5; 95% CI 2.1, 2.8). Overall, significantly more LMPT infants were classified with developmental delay when chronological (18.3%) versus corrected (15.0%) age was used (p=0.016). ConclusionsCorrecting for prematurity results in significantly higher developmental test scores and a significantly lower prevalence of developmental delay in LMPT infants and may affect eligibility for intervention services. Researchers and clinicians should be aware that the use of corrected age may impact on developmental test scores at both an individual and population level among infants born LMPT.

School context and gender differences in mathematical performance among school graduates in Russia

Gender differences in mathematical performance have received considerable scrutiny in the fields of sociology, economics and psychology. We analyse a large data-set of high school graduates who took a standardised mathematical test in Russia in 2011 (n = 738,456) and find no substantial difference in mean test scores across boys and girls. However, boys have a greater variance of scores and are more numerous at the top of the distribution. We apply quantile regression to model the association between school characteristics and gender differences in test scores throughout the distribution of test scores. Male advantage in test scores, particularly at the top of the distribution, is concentrated in cities and in the schools with an advanced curriculum. In other high schools, especially in the countryside, gender differences in all parts of the distribution are small. We suggest several mechanisms based on selection and school effects that account for our findings.

A comparison of recreational water illness awareness and frequency of swimming

&#x0D; Objective: Swimming pools have potential to create health hazards that range from physical, chemical to biological. Biological concerns center on communicable diseases which can be spread through poor hygiene practices. To prevent the spread of disease, swimmers must be informed and practice appropriate hygiene. This study aims to determine whether the frequency of swimming had an influence on swimming pool hygiene knowledge. Method: Survey questions focusing on risk factors for communicable disease spread, and personal hygiene practices were developed using the pool operation handbooks, input from environmental health instructors at the British Columbia Institute of Technology, as well as past surveys from other studies. Pool patrons were surveyed at Hillcrest Community Centre in Vancouver. Scores from these tests were then analyzed in NCSS9 using one-way ANOVA tests and Two-Sample t-tests. Results: 167 validated surveys were analyzed. The most often incorrectly answered questions were in regards to the duration of avoiding swimming after diarrheal illness, pre-swim hygiene, and after bathroom use hygiene. No statistically significant difference in mean test score was found in individuals that swam more than once a week, more than once a month, or less than once a month. Statistically significant differences in mean test scores were found for individuals that read signs, and age group. Conclusion: From the data, it is observed that those who swam more frequently were not more informed on pool hygiene issues than those who swam less. The sample size (n=167) for this conclusion may be too small, since beta value was 87.5%.&#x0D;

Gender Differences in Mathematical Performance and the School Context: Evidence from Russia

Gender differences in mathematical performance have been long debated in psychology, economics, and sociology. We contribute to this literature by analyzing a large data set of high school graduates who in 2011 took a standardized mathematical test in Russia (n = 738,456). We find no substantial difference in mean test scores of boys and girls. However, boys have a greater variance of scores and are more numerous at the top of the distribution. We apply quantile egression to model the association between school characteristics and gender differences in test scores throughout the distribution. Male advantage in test scores, particularly at the top of the distribution, is concentrated in cities and in schools with the advanced curriculum. In ordinary high schools, especially in the countryside, gender differences in all parts of the distribution are very small. A separate analysis at the regional level confirms that male advantage in mean test scores is higher in more urbanized regions.

Examining an Online Microbiology Game as an Effective Tool for Teaching the Scientific Process

This study investigates the effectiveness of the online Flash game Disease Defenders in producing knowledge gains for concepts related to the scientific process. Disease Defenders was specifically designed to model how the scientific process is central to a variety of disciplines and science careers. An additional question relates to the game’s ability to shift attitudes toward science. Middle school classes from grades six to eight were assigned to the experimental group (n = 489) or control group (n = 367) and asked to participate in a three-session intervention. The sessions involved completing a pretest, a game play session, and taking a posttest. Students in the experimental group played Disease Defenders while students in the control group played an alternative science game. Results showed a significant increase in mean science knowledge scores for all grades in the experimental group, with sixth grade and seventh grade students gaining more knowledge than eighth grade students. Additionally, results showed a significant positive change in science attitudes only among sixth graders, who also rated their satisfaction with the game more favorably than students in higher grades. No differences in mean test scores were found between genders for science knowledge or science attitudes, suggesting that the game is equally effective for males and females.

Academic Performance in Adolescence after Inguinal Hernia Repair in Infancy

Although animal studies have indicated that general anesthetics may result in widespread apoptotic neurodegeneration and neurocognitive impairment in the developing brain, results from human studies are scarce. We investigated the association between exposure to surgery and anesthesia for inguinal hernia repair in infancy and subsequent academic performance. Using Danish birth cohorts from 1986-1990, we compared the academic performance of all children who had undergone inguinal hernia repair in infancy to a randomly selected, age-matched 5% population sample. Primary analysis compared average test scores at ninth grade adjusting for sex, birth weight, and paternal and maternal age and education. Secondary analysis compared the proportions of children not attaining test scores between the two groups. From 1986-1990 in Denmark, 2,689 children underwent inguinal hernia repair in infancy. A randomly selected, age-matched 5% population sample consists of 14,575 individuals. Although the exposure group performed worse than the control group (average score 0.26 lower; 95% CI, 0.21-0.31), after adjusting for known confounders, no statistically significant difference (-0.04; 95% CI, -0.09 to 0.01) between the exposure and control groups could be demonstrated. However, the odds ratio for test score nonattainment associated with inguinal hernia repair was 1.18 (95% CI, 1.04-1.35). Excluding from analyses children with other congenital malformations, the difference in mean test scores remained nearly unchanged (0.05; 95% CI, 0.00-0.11). In addition, the increased proportion of test score nonattainment within the exposure group was attenuated (odds ratio = 1.13; 95% CI, 0.98-1.31). In the ethnically and socioeconomically homogeneous Danish population, we found no evidence that a single, relatively brief anesthetic exposure in connection with hernia repair in infancy reduced academic performance at age 15 or 16 yr after adjusting for known confounding factors. However, the higher test score nonattainment rate among the hernia group could suggest that a subgroup of these children are developmentally disadvantaged compared with the background population.

Comparison of Web-Versus Classroom-Based Basic Ultrasonographic and EFAST Training in 2 European Hospitals

Training physicians in new skills through classroom-based teaching has inherent cost and time constraints. We seek to evaluate whether Web-based didactics result in similar knowledge improvement and retention of basic ultrasonographic principles and the Extended Focused Assessment with Sonography for Trauma (EFAST) compared with the traditional method. Physicians from 2 German emergency departments were randomized into a classroom group with traditional lectures and a Web group who watched narrated lectures online. All participants completed a pre- and posttest and a second posttest 8 weeks later. Both groups underwent hands-on training after the first posttest. A control group completed the 2 initial tests without didactic intervention. Fifty-five subjects participated in the study. Both the classroom and Web group showed significant improvement in pre- and posttest 1 scores (75.9% versus 93.9% and 77.8% versus 92.5%; P<.001 for both), with similar knowledge retention after 8 weeks (88.6% and 88.9%; P=.87). No statistically significant difference in mean test scores could be found between the 2 groups at each point: -1.9% (95% confidence interval [CI] -5.2% to 1.4%) for the pretest, 1.4% (95% CI -0.6% to 3.4%) for posttest 1, and -0.3% (95% CI -3.9% to 3.3%) for posttest 2. The control group showed no learning effect without intervention (83.3% versus 82.8%, ; P=.88). Web-based learning provides the potential to teach physicians with greater flexibility than classroom instruction. Our data suggest that Web-based ultrasonography and EFAST didactics are comparable to traditional classroom lectures and result in similar knowledge retention.

An Exploratory Study of the Effects of Time Compressed Animated Delivery Multimedia Technology on Student Learning in Reproductive Physiology

Two experiments examined the effects of a multimedia technology referred to as “Time Compressed Animated Delivery” (TCAD), on student learning in a junior-level reproductive physiology course. In experiment 1, participating students received one of two presentations of the same instructional material: TCAD and a lecture captured on video. At the completion of each presentation a test was administered and group mean test scores computed and compared. The results were statistically significant (df = 362, t = 10.623, p < 0.05), favoring the TCAD treatment group. The effect size estimate was 1.14. In experiment 2, student learning from three groups were compared on the same reproductive physiology unit used in experiment 1: (1) TCAD, (2) TCAD without the 3-D component, and (3) video-lecture. After removal of three poor functioning items, a one-way analysis of variance was computed. The results were statistically significant (df = 2, F = 2.351, p < 0.10). Results of post hoc comparisons showed that differences in mean test scores between the TCAD and control groups were statistically significant (p < 0.05). The effect size estimate was 0.25. These findings provide preliminary evidence for use of TCAD.

Neuropsychological Performance 10 Years After Immunization in Infancy With Thimerosal-Containing Vaccines

Thimerosal, a mercury compound used as a preservative in vaccines administered during infancy, has been suspected to affect neuropsychological development. We compared the neuropsychological performance, 10 years after vaccination, of 2 groups of children exposed randomly to different amounts of thimerosal through immunization. Children who were enrolled in an efficacy trial of pertussis vaccines in 1992-1993 were contacted in 2003. Two groups of children were identified, according to thimerosal content in vaccines assigned randomly in the first year of life (cumulative ethylmercury intake of 62.5 or 137.5 microg), and were compared with respect to neuropsychological outcomes. Eleven standardized neuropsychological tests, for a total of 24 outcomes, were administered to children during school hours. Mean scores of neuropsychological tests in the domains of memory and learning, attention, executive functions, visuospatial functions, language, and motor skills were compared according to thimerosal exposure and gender. Standard regression coefficients obtained through multivariate linear regression analyses were used as a measure of effect. Nearly 70% of the invited subjects participated in the neuropsychological assessment (N = 1403). Among the 24 neuropsychological outcomes that were evaluated, only 2 were significantly associated with thimerosal exposure. Girls with higher thimerosal intake had lower mean scores in the finger-tapping test with the dominant hand and in the Boston Naming Test. Given the large number of statistical comparisons performed, the few associations found between thimerosal exposure and neuropsychological development might be attributable to chance. The associations found, although statistically significant, were based on small differences in mean test scores, and their clinical relevance remains to be determined.