Low-confidence responses on the vocabulary size test

Abstract

McDonald and Asaba (Vocabulary Learning and Instruction, 2015) reported an administration of the Vocabulary Size Test that was modified to include ”I don’t know” as a fifth response option on all items, and in which participants later responded to the items originally marked as ”I don’t know”. McDonald and Asaba were inclined to favour the score calculated without the later (reluctant or low-confidence) responses. It is argued here that this goes beyond the data. In many educational contexts,strong encouragement is given to respond when unsure, as examinees to have a better-than-chance probability of being correct, and will be disadvantaged if they do not respond.