title: Retest variability of human infant contrast sensitivity: how many tests are sufficient?
abstract: Retest variability of a new infant contrast sensitivity (CS) card procedure was assessed by binocular measurement of a group of 20 6-month-olds twice within a 1-week period. Coefficient of reliability analyses showed that within-subject variability between tests was only slightly less than variation across subjects, which suggests that results from a single test are a poor predictor of an infant's "true" visual functioning. To determine how many tests are needed to estimate when infant CS stabilizes to within an acceptable (0.15 log unit) criterion, a second experiment was conducted in which a small group of subjects was tested repeatedly over a 2-week period. The results showed that averaging performance on 2 to 3 tests was required before an accurate estimate of the subject's performance could be obtained. Our results suggest that caution should be taken in the interpretation of a single measurement of infant visual functioning.
authors.affiliation: Department of Psychology, Memorial University of Newfoundland, St. John's, Canada. michelem@morgan.ucs.mun.ca
authors.forename: R J
authors.initials: RJ
authors.lastname: Adams
authors.forename: M L
authors.initials: ML
authors.lastname: Courage
authors.forename: J R
authors.initials: JR
authors.lastname: Drover
mesh_terms: D015350:Contrast Sensitivity / Q000502:physiology*; D005260:Female; D006801:Humans; D007223:Infant; D008297:Male; D015588:Observer Variation; D015203:Reproducibility of Results; D014787:Vision Tests / Q000592:standards*; D015348:Vision, Binocular / Q000502:physiology