Loy is correct about tests. The WJ has better ceilings, since it's not as tied to item sets, unlike the WIAT and KTEA, which both have item sets for reading comprehension and written expression. All three tests have issues with composites for 4-year-olds. The WJ, in particular, sometimes gives questionable composite scores, because of the data available in the standardization sample. The other two simply don't have composites available at this age level for some areas (the KTEA has a Reading Composite and an Oral Language Composite, the WIAT has only an Oral Language Composite). From the child-friendly standpoint, both the KTEA and WIAT are more accessible than the WJ, and thus more likely to elicit optimal performance.