Research indicates that aging processes include changes in health, social, and financial resources. A study was conducted to determine if three quantitative approaches to the measurement of longitudinal change would yield similar results when the relationship between subjective well-being and measures of health, social, and financial resources were analyzed. Three measures of longitudinal change were used, including difference scores, residual change scores, and percentage gain scores. Data were taken from the Retirement History Study by the Social Security Administration and the sample included 8922 respondents measured in 1969, 1971, and 1973. The dependent variable measured happiness. Health resources were measured by the General Disability and Overall Disability Indexes with a high score representing a high degree of disability. Social resources were measured by the Scope of Immediate Family and Size of Immediate Family Indexes, with high scores indicating that the respondent had a spouse, parent, child, and sibling. Respondents reported more disability and fewer social resources as they aged. When the approach to the measurement of change was varied, different results were obtained in terms of the amount of variance explained and in terms of the relative importance of the resource area for predicting happiness and change in happiness outcome. The use of difference scores and residual change scores together is needed in measurement of change in aging studies. (ABL)