PSYC 421 Week 5 DB Forum 2 Example

Discussion Board Forum 2: Thread and Two Replies

PSYC 421 Psychological Measurement, Discussion Board Forum 2 (thread and two replies)

Thread by [Student Name]

The prompt and the classmates' posts are composites standing in for the course's own forum; the textbook and the journal articles are real and described from their published sources; the requirements follow Liberty's public course guide for PSYC 421.

Thread

Imagine that a nine-year-old is evaluated for a learning concern and earns a full scale IQ of 72 on an intelligence test whose norms were gathered fifteen years earlier. If she had been tested on a newly normed edition, her score might have been several points lower, perhaps below 70, a range that can affect eligibility for services. Her ability did not change; the reference group did. The same child, on the same day, could be described in two quite different ways depending on which edition the evaluator happened to pull from the shelf.

Cohen and Swerdlik (2018) describe the Flynn effect as the observed rise in intelligence test performance over time, which means that norms become obsolete. A test normed years ago compares today's test takers with an earlier population that, on average, scored lower on the same items. The result is inflated scores, a problem the test publishers address by renorming tests periodically.

How large is the effect? Trahan et al. (2014) gathered 285 studies, 14,031 people in all, in which the same individuals sat two intelligence tests whose norms had been collected in different years. The average gain was 2.31 standard score points per decade. For modern Stanford-Binet and Wechsler tests normed since 1972, the estimate was 2.93 points per decade, consistent with the common rule of about 3 points, and the data gave no sign that the effect was fading.

Pietschnig and Voracek (2015) took a longer view, analyzing 271 samples with almost 4 million participants from 31 countries between 1909 and 2013. They found gains of about 0.28 full scale IQ points per year, larger for fluid than crystallized intelligence and larger for adults than for children. Unlike Trahan and colleagues, they found that gains had decreased in recent decades.

The two analyses differ in their samples and methods, so they are not simply contradictory, but together they show that the size of the effect is uncertain enough that test users should know the norm date of every test they give. For a child near a cutoff, that date can matter as much as the score itself. It also suggests that evaluators should report the norm year in every written report, so that anyone reading the score later knows which reference group it came from.

Classmates: should evaluators adjust scores for outdated norms, or simply use the newest test available?

Reply to Alicia

Alicia, your point about death penalty cases shows how much a few IQ points can matter. Since the Supreme Court's 2002 Atkins ruling barred the execution of people with intellectual disability, scores near the cutoff have become central in some capital trials. Cohen and Swerdlik (2018) note that intellectual disability is defined by both intellectual functioning and adaptive behavior, so an IQ score is never the only evidence. Still, if a defendant scored 73 on a test normed many years earlier, a Flynn adjustment of about 3 points per decade, as estimated by Trahan et al. (2014) for modern tests, could place the true score in the disability range. Courts have disagreed about whether to apply such corrections, partly because the size of the effect varies across studies, as Pietschnig and Voracek (2015) showed. I lean toward reporting both the obtained score and an adjusted estimate, with the standard error of measurement, so the court sees the full uncertainty rather than a single number.

Reply to Brian

Brian, you suggested that schools should always use the most recently normed test to avoid the Flynn problem. I agree that this is the best starting point, and Cohen and Swerdlik (2018) emphasize that test users are responsible for choosing instruments with current, appropriate norms. But there are practical complications. A child may have been tested two years ago on an older edition, and comparing that score with a new one can make it look as though the child's ability declined, when the difference reflects the change in norms. Trahan et al. (2014) found that the effect was larger in validation research samples than in standardization samples, which suggests that context affects how big the gap looks. Schools might therefore record the norm year with every score in a student's file and train evaluators to interpret score changes across editions with care, especially when eligibility decisions are being revisited at a three-year reevaluation.

References

Cohen, R. J., & Swerdlik, M. E. (2018). Psychological testing and assessment: An introduction to tests and measurement (9th ed.). McGraw-Hill Education.

Pietschnig, J., & Voracek, M. (2015). One century of global IQ gains: A formal meta-analysis of the Flynn effect (1909-2013). Perspectives on Psychological Science, 10(3), 282-306. https://doi.org/10.1177/1745691615577701

Trahan, L. H., Stuebing, K. K., Fletcher, J. M., & Hiscock, M. (2014). The Flynn effect: A meta-analysis. Psychological Bulletin, 140(5), 1332-1360. https://doi.org/10.1037/a0037173