This study sought to better understand search performance using an online portal containing a collection of heterogeneous library resources for K-12 students. Search performance is examined in terms of search success, search time, strategy, and effort. This study revealed unsuccessful searches tended to take longer than successful searches; preference of search strategy (searching vs. browsing) did not affect search success outcome; students tended to perform well in tasks for which they were able to use various strategies, and unsuccessful searches tended to use more effort--more mouse clicks, more keystrokes, more queries, more sites visited, and more strategy shifts. Implications of the study are also discussed. (Contains 1 figure and 14 tables.)