Hopes by NBC's rivals that they would pick up viewers who deserted the network when it installed Jay Leno in the 10 00 p.m. hour have not materialized, according to an analysis of ratings research in the hour. Although NBC has indeed lost an average of 2.4 million viewers in the hour, they have fled not to the other networks but to DVRs, the wire service said. CBS is down in three of the five nights opposite Leno in the 10 00 hour and ABC is down in all of them. (Fox does not air national programming at 10 00 p.m.) "The DVR phenomenon is a little bit higher than we though," David Poltrack, who tracks ratings for CBS, acknowledged in an interview with the wire service. Many DVR users are indeed watching other CBS programs during the time period, but DVR playback is downgraded by advertisers since many viewers fast-forward through commercials. Nevertheless, Poltrack told the A.P., "You'd rather have a playback viewer than nothing at all."