BY CONDUCTING AT LEAST TWO SURVEYS AT DIFFERENT POINTS IN TIME IN THE SAME POPULATION, IT IS POSSIBLE TO DISCOVER HOW CHANGES IN DEMOGRAPHIC AND OTHER VARIABLES OVER TIME AFFECT CHANGES IN THE DISTRIBUTION OF LEGAL PROBLEMS AND THE USE OF LAWYERS AND TO SPECIFY HOW THE PROCESS BY WHICH THE LEGAL PROFESSION IS MOBILIZED CHANGES OVER TIME. COHORT ANALYSIS AND ECONOMETRICS CONSTITUTE THE PROPOSED METHODOLOGY FOR THE STUDY OF LEGAL CHANGE. THEORETICAL ASPECTS OF THE QUANTITATIVE STUDY OF LAW ARE EXPLORED, AND AN ATTEMPT IS MADE TO SHOW HOW COHORT ANALYSIS CAN BE USED TO EVALUATE CHANGES IN THE LEGAL PROCESS. SINCE IT IS LIKELY THAT THE EXISTING DISTRIBUTION OF LEGAL PROBLEMS IS A PRODUCT OF STRONG COHORT AND AGING EFFECTS, SERIOUS QUESTIONS ARE RAISED ABOUT INTERPRETATIONS OF DATA ON LEGAL PROBLEMS. IT IS DIFFICULT TO DETERMINE WHETHER CORRELATES OF REPORTED LEGAL PROBLEMS ARE CORRELATES OF ACTUAL INCIDENCE RATES OR CORRELATES OF PERCEPTION, OR BOTH. A SIMPLIFIED MODEL OF THE LEGAL PROCESS THAT INVOLVES TWO EXOGENOUS INDEPENDENT VARIABLES (EDUCATION AND INCOME) AND TWO ENDOGENOUS, DICHOTOMOUS DEPENDENT VARIABLES (OCCURRENCE OF A LEGAL PROBLEM AND USE OF A LAWYER) IS DETAILED. THE MODEL IS SEQUENTIAL IN NATURE BECAUSE IT ASSUMES THAT LEGAL PROBLEMS OCCUR PRIOR TO THE DECISION TO OBTAIN LEGAL ASSISTANCE. TWO KINDS OF LEGAL CHANGE IMPLIED IN THE MODEL ARE THE CHANGE IN THE RATE AT WHICH LEGAL ASSISTANCE IS SOUGHT FOR GIVEN LEGAL PROBLEMS AND CHANGES EXTERNAL TO THE LEGAL SYSTEM. A COMBINED STRATEGY INVOLVING COHORT ANALYSIS AND THE SEQUENTIAL MODEL IS DISCUSSED. REFERENCES AND SUPPORTING DATA ARE INCLUDED. (DEP)