Background: While the literature on strategy use is relatively mature, measures of strategy use overwhelmingly measure only one aspect of that use, frequency, when relating that strategy use to performance outcomes. While this might be one important attribute of strategy use, there is increasing evidence that quality and conditional use of cognitive and metacognitive strategies may also be important. Aims: This study examines how multiple aspects of strategy use, namely frequency, quality, and conjunctive use of strategies, influence task performance on both well- and ill-structured task outcomes in addition to other concomitant variables that may interact with strategic processing during reading. Sample: The sample consisted of 21 high school students enrolled in an upper-level biology class in a suburban school in the north-eastern United States. Methods: These participants completed measures of prior knowledge and interest, then read either an expository or persuasive text while thinking aloud. They then completed a passage recall and open-ended response following passage completion. Results: In general, quantity was not positively related to the study outcomes and was negatively related to one of them. Quality of strategy use, on the other hand, was consistently related to positive reading outcomes. The influence of knowledge and interest in terms of strategies is also discussed as well as six cases which illustrate the relation of aspects of strategy use and the other concomitant variables. Conclusions: Evaluating strategy use by solely examining the frequency of strategy use did not explain differences in task performance as well as evaluating the quality and conjunctive use of strategies. Further, important relations between prior knowledge, interest, and the task outcomes appeared to be mediated and moderated by the aspects of strategy use investigated.