Derivational analogy is a technique for reusing problem solving experi
ence to improve problem solving performance. This research addresses a
n issue common to all problem solvers that use derivational analogy: o
vercoming the mismatches between past experiences and new problems tha
t impede reuse. First, this research describes the variety of mismatch
es that can arise and proposes a new approach to derivational analogy
that uses appropriate adaptation strategies for each. Second, it compa
res this approach with seven others in a common domain. This empirical
study shows that derivational analogy is almost always more efficient
than problem solving from scratch, but the amount it contributes depe
nds on its ability to overcome mismatches and to usefully interleave r
euse with from-scratch problem solving. Finally, this research describ
es a fundamental tradeoff between efficiency and solution quality, and
proposes a derivational analogy algorithm that can improve its adapta
tion strategy with experience.