Concept:A longitudinal approach involves repeated observations of the same subjects over a period of time to study changes. Among research methods, surveys are commonly used for this purpose.
Explanation:A longitudinal study collects data from the same group multiple times, tracking changes in variables.
Surveys can be designed as longitudinal studies, especially when studying a large population by repeatedly sampling the same individuals over weeks, months, or years.
For example, the 1970 British Cohort Study repeatedly surveyed the same 17,000 people from birth, making it a longitudinal survey.
The other options do not fit:
- Case study focuses on a few individuals in depth, not necessarily over time with repeated measures.
- Experimentation tests cause and effect under controlled conditions, not typically longitudinal.
- Introspection is self-examination of one’s own thoughts, not a repeated data collection approach.
Thus, among the given choices, the survey method best represents the longitudinal approach of investigation.
Answer:C. Survey