Which of the following methods is used to ensure unbiased data collection in surveys?

The correct choice is the use of random sampling techniques, which is essential for enhancing the reliability and validity of survey results. This method ensures that every individual in the population has an equal chance of being selected for the survey, effectively minimizing bias. By employing random sampling, researchers can obtain a representative sample that reflects the diversity of the population, which is crucial for generalizing the findings.

This approach contrasts with other methods like self-selection surveys, which can lead to biased results since participants choose themselves, often resulting in a sample that does not accurately represent the larger population. Random assignment of participants is primarily utilized in experimental designs rather than in survey collection, focusing on evenly distributing characteristics across groups rather than ensuring unbiased sampling. Convenient sampling, on the other hand, involves selecting individuals who are easiest to reach, which often introduces significant bias and limits the generalizability of the findings. Thus, random sampling techniques stand out as the most effective method for ensuring unbiased data collection in surveys.