Editing Intelligence quotient (section)

===Test bias or differential item functioning===
Differential item functioning (DIF), sometimes referred to as measurement bias, is a phenomenon when participants from different groups (e.g. gender, race, disability) with the same [[Latent trait|latent abilities]] give different answers to specific questions on the same IQ test.<ref>Embretson, S. E., Reise, S. P. (2000).''Item Response Theory for Psychologists''. New Jersey: Lawrence Erlbaum.</ref> DIF analysis measures such specific items on a test alongside measuring participants' latent abilities on other similar questions. A consistent different group response to a specific question among similar types of questions can indicate an effect of DIF. It does not count as differential item functioning if both groups have an equally valid chance of giving different responses to the same questions. Such bias can be a result of culture, educational level and other factors that are independent of group traits. DIF is only considered if test-takers from different groups ''with the same underlying [[Latent variable|latent]] ability level'' have a different chance of giving specific responses.<ref name=":1">{{cite journal |last1=Zumbo|first1=B.D. |year=2007|title=Three generations of differential item functioning (DIF) analyses: Considering where it has been, where it is now, and where it is going |journal=Language Assessment Quarterly |volume=4 |issue=2 |pages=223–233|doi=10.1080/15434300701375832|s2cid=17426415}}</ref> Such questions are usually removed in order to make the test equally fair for both groups. Common techniques for analyzing DIF are [[item response theory]] (IRT) based methods, Mantel-Haenszel, and [[logistic regression]].<ref name=":1" />

A 2005 study found that "differential validity in prediction suggests that the [[Wechsler Adult Intelligence Scale|WAIS-R]] test may contain cultural influences that reduce the validity of the WAIS-R as a measure of cognitive ability for Mexican American students,"<ref>{{cite journal|last1=Verney|first1=SP|last2=Granholm |first2=E|last3=Marshall|first3=SP|last4=Malcarne|first4=VL|last5=Saccuzzo|first5=DP|year=2005 |title=Culture-Fair Cognitive Ability Assessment: Information Processing and Psychophysiological Approaches |journal=Assessment|volume=12|issue=3|pages=303–19|doi=10.1177/1073191105276674|pmid=16123251 |s2cid=31024437}}</ref> indicating a weaker positive correlation relative to sampled white students. Other recent studies have questioned the culture-fairness of IQ tests when used in South Africa.<ref>{{cite journal|last1=Shuttleworth-Edwards|first1=Ann|last2=Kemp|first2=Ryan|last3=Rust |first3=Annegret |last4=Muirhead|first4=Joanne|last5=Hartman|first5=Nigel|last6=Radloff|first6=Sarah|year=2004|title=Cross-cultural Effects on IQ Test Performance: AReview and Preliminary Normative Indications on WAIS-III Test Performance |journal=Journal of Clinical and Experimental Neuropsychology|volume=26|issue=7|pages=903–20 |doi=10.1080/13803390490510824 |pmid=15742541 |s2cid=16060622}}</ref><ref>{{cite journal|last1=Cronshaw |first1=Steven F. |last2=Hamilton|first2=Leah K.|last3=Onyura|first3=Betty R. |last4=Winston |first4=Andrew S. |year=2006|title=Case for Non-Biased Intelligence Testing Against Black Africans Has Not Been Made: A Comment on Rushton, Skuy, and Bons (2004)|journal=International Journal of Selection and Assessment |volume=14|issue=3|pages=278–87|doi=10.1111/j.1468-2389.2006.00346.x |s2cid=91179275}}</ref> Standard intelligence tests, such as the Stanford–Binet, are often inappropriate for [[autistic]] children; the alternative of using developmental or adaptive skills measures are relatively poor measures of intelligence in autistic children, and may have resulted in incorrect claims that a majority of autistic children are of low intelligence.<ref>{{cite journal|last1=Edelson|first1=M. G. |year=2006|title=Are the Majority of Children With Autism Mentally Retarded?: A Systematic Evaluation of the Data|journal=Focus on Autism and Other Developmental Disabilities |volume=21|issue=2|pages=66–83 |doi=10.1177/10883576060210020301|s2cid=145809356}}</ref>