Authors conducted a meta-analysis of diagnostic studies for language impairment in bilingual children and found a serious lack of necessary psychometric measures in the vast majority of studies examined.
A standard deviation (SD) is a quantity derived from the distribution of scores from a normative sample and can be defined as the average distance (or deviation) from the mean.
The terms normative sample and standardization sample refer to the same concept and are often used interchangeably. A norm referenced test uses a normative or standardization sample from the general population to determine what is “typical” or “normal” in that population.
Validity refers to the degree to which an item is measuring what it’s actually supposed to be measuring.
Reliability is the degree of consistency of measurement in a test. A test has a high degree of reliability if it produces similar results consistently under similar conditions.
The standard error of measure indicates the amount of uncertainty that a sample (such as a normative sample) is truly representative of the general population. In the case of administering standardized tests, it conveys the level of uncertainty that a single test performance observed by the evaluator represents how the child would do if it were administered multiple times.
