As digital video recorder (DVR) use has increased, so has time spent watching television — both throughout the day and during prime time — according to The Nielsen Company, writes MarketingCharts.

In DVR homes, television usage (live viewing plus DVR playback) for persons 18-49 was 3 percent higher at 9:00 PM and 5 percent higher between 11:00 PM and midnight in November 2007 than two years earlier, when penetration was very low, Nielsen said.

Nielsen accordingly speculates that as the number of DVR-owning households in the US population grows, DVR prime time viewing levels will likely rise as well.

The traditional prime time period (8-11 PM) is expanding as people create their own "personal television schedules" and push prime time as far back as midnight, the findings imply:

• 11 percent of viewers age 18-49 in DVR homes are playing back recorded programming between 9 and 10 PM.
• 7 percent are playing back programming between 11 PM and 12 AM.

For more findings, see MarketingCharts's coverage, including info on three distinct groups of DVR users based on how much they time-shift.