A number of assessment measures are available for measuring affective growth in reading. Among the factors involved in affective response to reading are attitude toward reading, interest in reading, and attitude toward specific reading programs. The most commonly used of the reactive measures of affective reading growth (those in which participants are aware that the measurement is being taken) is the self-reporting questionnaire or inventory. Inventories are available to measure elementary and secondary school students' attitudes toward leisure time reading and reading as a school subject. Other reactive measures include teacher interviews and student journals and diaries. In interpreting the results of reactive measures, it should be recognized that responses may not be a true indication of participants' behavior. Nonreactive measures (those in which participants are not aware that they are being assessed) include physical evidence regarding library use; systematic, planned observation of students, which may be aided by observation checklists or scales; spontaneous observation; and archival records reporting student attendance, library circulation, and disciplinary actions. Chances for success in assessing reading attitudes are greatest if a variety of reactive and nonreactive measures are used. (GW)