A crucial difference between representations of relative error inthese equations compared withEquations 6and7 for the single-facet designs is that three sources of measurement error varianceare separately represented, withpt2ntequaling specific-factor error,po2noequaling transient error, andpto,e2ntnoequaling random-responseerror. Effects fortasks, occasions, and their interaction are includedin the denominator for the D-coefficient but not the G-coefficientbecause those effects can change the absolutemagnitude of scoresbut not their relative differences.