Which Audience Analysis Measurements Principles and Techniques are Most Effective, and Why?

Surveying mass audiences is very helpful to the media to get feedback from their viewers. There are many ways in which companies analyze their audiences. They include the following: surveying, probability sampling, quota sampling, evaluating surveys, latter-day straw polls, newspaper and magazine audits, broadcast ratings, engagement ratings, interviews, diaries, people meters, the Media Metrix, A2M2, focus groups, sit-down interviews, galvanic skin checks, prototype research, demographics, cohort analysis, and geodemographics.

Out of these, I believe that Probability Sampling is most effective. With probability sampling, everyone in the population being surveyed has a equal chance to be sampled. They also have control over the number of people being surveyed. For each sampling, they choose 384 people that are properly selected for results to provide 95% confidence that the results have less than 5% margin of error.

Since their confidence in this is so high, and there seems to be little loop holes, this is the most effective audience analysis measurement technique.