The study on Global Ageing and Adult Heath (SAGE) examines trends in aging among 66,000 people in multiple countries unfolding over many years. As is true of most longitudinal studies, this need for years of data collection results in high costs. By contrast, a relatively straightforward sociology study, such as one that is merely trying to identify the average age at which people in a given city first become parents, may not need a large budget because ____
Which choice most logically completes the text?
Explanation
Context: The passage contrasts expensive longitudinal studies (SAGE, which needs years of data) with simpler sociology studies. The blank explains why the simpler study doesn't need a large budget. The clue: "relatively straightforward" and "merely trying to identify the average age."
Answer: D) the sociology study can be done well without years of data collection.
Why? SAGE's high cost is directly tied to years-long data collection. A study that doesn't need that timeline logically doesn't need a large budget — D completes this contrast exactly.
Traps:
- A) longitudinal methods suitable → contradicts the passage's contrast between the two types
- B) SAGE adding questions → irrelevant to why the sociology study costs less
- C) 66,000 is enough → discusses SAGE's sample size, not the sociology study's budget