A television audience measurement system measures viewing of a television program viewed on digital television located in a statistically selected site by (i) retrieving an audience measurement data packet from a television set in order to identify the television program, (ii) detecting an audio code embedded in the television program in order to identify the television program, (iii) extracting an audio signature from the television program in order to identify the television program, (iv) identifying the television program through use of a software agent, and (v) selecting at least one of the retrieving means, the detecting means, the extracting means, and the software agent in order to identify the television program.