A researcher's analysis of a situation before receiving any data from the forecast horizon. A priori analysis might rely on domain knowledge for a specific situation obtained by interviewing experts or information from previously published studies. In marketing, for example, analysts can use meta-analysis to find estimates of price elasticity (for example, see Tellis 1988) or advertising elasticity (Sethuraman and Tellis 1991). To obtain information about prior research, one can search the Social Science Citation Index (SSCI) or A Bibliography of Business and Economic Forecasting (Fildes, Dews and Howell 1981). The latter contains references to more than 4,000 studies taken from 40 journals published from 1971 to 1978. A revised edition was published in 1984 by the Manchester Business School, Manchester, England. It can guide you to older sources that are difficult to locate using electronic searches. Armstrong (1985) describes the use of a priori analysis for econometric models.