This monograph is part of a series on second language research methodology edited byGassand Schachter. Their introduction to the text highlights the interdisciplinary nature of SLAresearch and the necessity for a fuller understanding of the wide variety ofresearchmethodologies in current use. Each monograph is devoted to a particular datacollection methodor instrument and provides an overview of (a) the theoretical andresearch background, (b) thecurrent uses of the instrument or method, (c) appropriateresearch questions, (d) underlyingassumptions, and (e) any problems associated withpractical use. Forthcoming texts will covercase studies, conversation analysis, elicitedimitation, data-driven modeling, and speechacts.