Most approaches to determining effectiveness in early intervention emphasize data collection procedures that are objective, unbiased, and reliable. Subjective views held by individuals usually are considered unreliable, and less relevant to early intervention efficacy research. However, systematic investigations of how early intervention services are viewed subjectively by both recipients and providers can facilitate the interpretation of efficacy data gained when more traditional, objective methods are used. This article describes Q methodology, a technique that can be used to gain important insights on individuals' judgments, attitudes, and points of view on topics or situations that involve early intervention effectiveness issues. Examples of Q application drawn from the extant literature of several disciplines are used to indicate how the technique might be used to address important questions of early intervention effectiveness. Specific steps involved in Q methodology are illustrated in a description of an early intervention efficacy study designed to explore views of family-centered practices held by family members of children enrolled in early intervention programs. © 1998, SAGE Publications. All rights reserved.