Retailers and manufacturers will soon be able to chart the effectiveness of in-store promotions the same way Nielsen rates TV shows, box-office results, and online ads. Using in-store cameras, infrared sensors, and human “counters,” a project called P.R.I.S.M. (Pioneering Research for In-Store Metrics) will create the first global metric for evaluating the retail environment as a marketing medium.

The project — a joint effort of the Nielsen Company, the In-Store Marketing Institute, manufacturers, and retailers — has been in development since early 2006. But last week, in a story about a session on P.R.I.S.M. at the Advertising Research Foundation’s Re:think Conference and Expo, Retail Week reported that the long-awaited P.R.I.S.M. will launch in stores nationwide in July.