When do purchase intentions predict sales?

Marketing managers routinely use purchase intentions to predict sales. The purpose of this paper is to identify the factors associated with an increased or decreased correlation between purchase intentions and actual purchasing. Using two studies, we examine the data collected from a wide range of different settings which reflect the real world diversity in how intentions studies are conducted. The results indicate that intentions are more correlated with purchases: 1) for existing products than for new ones; 2) for durable goods than for non-durable goods; 3) for short than for long time horizons; 4) when respondents are asked to provide intentions to purchase specific brands or models than when they are asked to provide intentions to buy at the product category level; 5) when purchases are measured in terms of trial rates than when they are measured in terms of total market sales; and 6) when purchase intentions are collected in a comparative mode than when they are collected monadically.