New recommended guidelines for local TV stations have been approved for analysis of audience projections before and after a TV commercial airs, according to a joint statement between the Coalition for Innovative Media Measurement (CIMM) and the Television Bureau of Advertising (TVB).

One major change is a new guideline that looks to amass viewing over a four-week period -- rather than a single telecast or a small number of telecasts.

CIMM and the TVB say a four-week aggregation of advertising units for post analysis should have no day- or date-based post analysis. This should improve the reliability of audiences. 

The recommendation includes a 90% posting threshold, meaning that if a projected rating is around 90% of the measured post-analysis rating, no makegoods are owed.

Special highly viewed events such as one-time programs would be exempt from the four-week period -- such as the Super Bowl, the Academy Awards and sports playoffs.

Conversely, programs with smaller audiences and sample sizes may need greater aggregation than the four week guideline.

The Post Analysis Guidelines are the first of three co-funded projects co-developed by CIMM and the TVB. 

The organizations say these new guidelines are needed as more viewing choices and greater fragmentation of audiences have diminished local TV viewing. 

In a statement, Jon Watts, managing director at CIMM, says: “This has a costly impact as the use of an unstable timing framework can penalize buyers for not meeting goals, and sellers can owe make-goods because of unreliable measurement, not because they under-delivered the audience.”

Kyle Poppie, vice president of data science at Nielsen, added: “Averaging across multiple weeks or months yields more reliable estimates... To really maximize the reliability of an estimate, assess the audience for the entire schedule or for all spots on a station, rather than a single telecast.”