COMING ATTRACTIONS

A showdown may be coming between nine Los Angeles television TV stations and the Arbitron and Nielsen ratings services. A committee of the stations has hired an outside firm to examine discrepancies between the ratings services’ estimates for certain age, income and ethnic categories. Although both rating services get their population data from a single source, they often gauge certain demographic categories very differently, a representative of the Los Angeles Television Stations Research Committee said. The rating services report divergent Latino population estimates, a problem that contributes to an ongoing undercount of Spanish-language viewers, said Mari-aala Massakas, research director of committee member KMEX-TV.