This investigation expands prior work on the fulfillment of party pledges (platforms) in the United Sates and United Kingdom. Prior work included a comparison of pledge fulfillment under Reagan and Thatcher, and an analysis of pledge fulfillment in the U.S on economic and social welfare policy from Carter to Bush. The investigators collect data using various legislative reference books, official budgets and statistics, secondary sources, and computer databases. Most of the United Kingdom work is done with resources available in the U.S., using secondary sources, bill texts, government publications and statistics, and party information. The researchers also examine archived party materials and conduct interviews with platform drafters and policy makers. The study contributes much to debates about the performance of democratic governments under various conditions. A consistent standard of performance--pledge fulfillment--is applied to two countries over an extended time period of time, facilitating valid comparisons between countries and time periods. The dataset will be of value to numerous scholars and substantially enhances our understanding of the topic.