What is a research instrument used to gather data from respondents in a uniform manner called?

The term that correctly identifies a research instrument used to gather data from respondents in a uniform manner is the survey. A survey systematically collects data from individuals, typically using structured formats that can include questionnaires or interviews. Surveys are designed to ensure that every respondent answers the same set of questions, which guarantees consistency and uniformity in the data collected.

While a questionnaire is indeed a tool used within a survey to gather responses, it is more specific and refers to the list of questions themselves. Interviews can serve as a method of data collection as well, but they tend to diverge from the uniformity that a survey strives to achieve, as they may allow for more flexible, open-ended responses. A form is a broader term that could encompass various types of documents used to collect data but does not specifically denote a standardized instrument in research settings like a survey does. Thus, referring to the entire structured process and method of collecting data gives rise to the term "survey".