Surveys often lack which of the following during the research process?

Surveys typically have a fixed structure once they are designed, which can limit changes after data collection has begun. This characteristic means that while surveys can be structured with specific questions and responses, any alteration to the survey after it has started can lead to inconsistencies in the data collected. This can impact the reliability and validity of the research findings, as modifying questions or procedures mid-survey can introduce bias or complicate data analysis.

In contrast, structured questions are a fundamental aspect of surveys, ensuring that responses are quantifiable and comparable. Defined sampling methods are critical for ensuring that the sample is representative of the larger population. Lastly, surveys are generally limited to specific types of data, such as quantitative responses, but can be designed to include some qualitative aspects depending on the research objectives. However, the inherent structure of surveys often results in a lack of flexibility once the survey has commenced, making the answer regarding the ability to be changed the most fitting.