Data collected by the Civil Litigation Research Project is used to investigate the questions of whether lawyers devote more or less effort and whether the variables affecting lawyer effort behave differently depending upon fee arrangement. Research analysis of data provides strong support for the hypothesis that fee arrangement affects the types of influences that many variables have on lawyer effort, but only partial support for the proposition that the amount of lawyer effort depends on fee arrangement. Indicators for independent variables measured include party interaction, case characteristics, nature of participants, participant goals, and processing and management. Results also indicate that the percentage fee-lawyers have an incentive to put in less effort than is in the best interest of the client. Since the marginal cost of lawyer effort to the client is zero, the client's best interests would require the lawyer to keep working on the case as long as the additional effort produces any increased return. Conclusions indicate that hourly fee-lawyers put in more effort on small cases than contingent fee-lawyers; however, no statistical evidence has been found to indicate a difference in effort for larger cases. Tabular data and 26 references are provided. (Author abstract modified)