Which audience analysis measurements principles and techniques are most effective, and why?

            The most effective audience analysis measurement principles and techniques are probability sampling, engagement ratings, interviews, and media metrix.  Each of these survey techniques uses fair ways to get the necessary information.  Probability sampling allows everyone in the population to have an equal chance to be surveyed.  Pioneered by George Gallup in the 1940s, probability sampling has four factors that contribute to a survey’s accuracy: sample size, sample selection, margin of error, and confidence.  The magic number 384 is used in most surveys as a good estimate of the population as a whole.  The confidence level, or percentage of the survey which is accurate, should be around 95%, with a margin of error around 5%.  Larger sampling can improve confidence levels.  A good way to figure out how interesting and popular a TV network or specific ad is would be through engagement ratings.  Engagement ratings keep track of and calculate the amount of time that the audience spends viewing advertisements on certain TV networks.  Interviews are very accurate because they are personal and involve face-to-face time with another person.  Interviews are extremely effective because people will often open up when talking directly to someone.  Lastly, media metrix, a leading service measuring Internet audience size, is effective because it uses a two-track system to determine how many people are viewing a certain website.  Overall, all four of these different techniques prove efficient when measuring and analyzing audiences.