Final answer:
The Literary Digest's polling method's main problem was non-random selection of its respondents, leading to a prediction that was not representative of the general population. Polls must have random, representative samples and clear questions to be accurate, and informed responses are preferable.
Step-by-step explanation:
The main problem associated with the polling methods of the Literary Digest was that its respondents were not randomly selected. The method used by Literary Digest involved sending opinion cards to their subscribers, as well as to those with a phone or car registration, which introduced a bias by only sampling a particular demographic that could afford such luxuries. This non-random sampling did not represent the general population adequately, as demonstrated in the 1936 presidential election prediction fail.
To ensure accurate predictions, it is essential to use random and representative samples in polls. It is also crucial to have clear and unbiased questions, a sufficient number of respondents, and a small margin of error. Pollsters might also consider assessing respondents' knowledge about the topic before taking the survey to ensure the results are informed and reliable.
Examples of polling companies producing results that incorrectly predicted public opinion include the push polls during the 2016 presidential primary, which used leading questions to sway respondents towards a specific answer. Likewise, there have been instances where declining response rates called into question the validity of survey estimates, as people were less likely to participate in telephone surveys over time.