Since observers' memory-based ratings of organizational phenomena provide data in research and decision-making contexts, bias in observers' judgments must be examined. A study was conducted to explore the extent to which leader behavior ratings are more generally biased by the availability heuristic. The availability heuristic is operative when a rater judges the frequency of occurrence of a behavior by the ease with which specific instances of that behavior can be remembered. The extent to which certain characteristics of behavior description items underly differences in the way examples of these behaviors are retrieved from memory was investigated. A literature review identified six possible determinants of availability differences between behavior description items. College students (N=96) rated each behavior description of the Leader Behavior Description Questionnaire (LBDQ) on one of the six identified availability components. All 100 items of the LBDQ were rated separately by 16 subjects for each availability component. The results strongly support the hypotheses that availability of items (i.e., more specific, valent, imagineable, dramatic, familiar and retrievable) would significantly correlate with actual ratings of leader behavior, reported in two previously published studies, and that these correlations would be larger when little actual stimulus behavior was present prior to rating compared to conditions where actual behavior was present. (Author/NB)