Over 150 published basic strategies for problem solving are documented and compared. "Nested" strategies are described. Research is summarized of the cognitive and attitudinal processing used when we solve problems. The connection between past problems that have been solved successfully, the subject knowledge, the current problem to be solved, and the problem solving process is described. "Problems" are distinguished from "exercises." Based on the research evidence, eleven criteria are posed for the creation of an evidence-based strategy. A resulting strategy is described. Suggestions are given about how to overcome the propensity to use the strategy as a series of linear, sequential steps. Evidence is summarized ofthe use and effectiveness ofthe proposed evidencebased strategy. Most successful problem solvers use a "strategy." In this paper, we survey published strategies, consider the research evidence about the appropriateness of using and teaching via strategies, summarize pertinent research evidence about the problem solving process and apply criteria to devise an evidence-based strategy for problem solving.
1. 150 PUBLISHED STRATEGIES
More than 150 basic strategies to solve problems in business, science, mathematics, engineering, design, military, music, art, psychology, history, nursing, medicine, and policing have been published.'-iso An analysis of these basic strategies shows:
* The published strategies are similar. Most start with words describing an "awareness of a problem"; most close with an evaluation or verification. Most have a "definition stage." Most have between two and seven stages.
. A fews9,'1.3,111,111 explicitly link the problem solving process with subject knowledge (context-specific knowledge), past experience and past solved problems.
Some strategies use a mnemonic acronym to aid recall and application: DO IT,77 IDEAL,99 SOLVE,"' ABCDE,"' and PHARMA.152 Some are variations on Polya's classic four-stage strategy,6 on the Creative Problem Solving strategy from the Creative Education Foundation,"-"s or on the McMaster Problem Solving (MPS) program."," Only the Nursing Profession uses a consistent strategy*'s7g worldwide, although variations have been published.6,"' Some propose different strategies for problem solving, decision-making, and writing?'15,127,139,142 Some refer to a strategy as a "framework"142; others as a "map""' and others show the strategy in the context of a computer program rather than as a strategy to guide individuals or students.150 Only a few authors'43,50,151 cite published research to support the names used in these basic strategies.
For complex problem situations, the published strategies may be notably different.58,152-161 The strategies proposed for such complex problems usually can be represented as a series proposed for such complex problems that can be solved using a basic strategy similar to those given by references 1-151. We refer to this application as the use of For example, Kepner Trego this application as the a trouble of nested strategies. For example, Kepner Tregoe58 solve a troubleshooting situation as a series of four subproblems: 1) Prioritize the problem, 2) Find the cause, 3) Correct the cause, and 4) Prevent the cause from reoccurring. A strategy published for Pharmacists can cause from represented as a nested strategy that applies the for Phame basic sts can be represented as a nested strategy to different parts of the overall problem."' In the analysis that applies the same basic strategy to different parts of the overall problem."' In the focus is on basic strategies'-'S' and not ones requiring nesting or the multiple application of a basic strategies'-"' and not ones requiring nesting or the multiple application of a basic strategy.
11. IS A STRATEGY USEFUL?
Since there are so many different strategies and since few are supported by research evidence, is it useful to have a strategy to solve problems? …