Capstone: Conducting a Real Research Project

Starting point: rather than searching for "does caffeine help exercise" and stopping at the first confident-sounding article, this project starts from the question itself and follows real evidence, actively looking for disagreement rather than only confirmation — the exact distinction Chapter 1 drew between casual searching and genuine research.

P: adults engaging in endurance exercise  ·  I: pre-exercise caffeine ingestion  ·  C: a placebo or no caffeine  ·  O: measured endurance performance (time to exhaustion, performance time). Assembled: "Among adults performing endurance exercise, does pre-exercise caffeine ingestion improve measured performance compared to a placebo?" — genuinely feasible, novel enough to be worth checking personally, ethical, and relevant (FINER).

The real evidence located is a meta-analysis of 21 randomized controlled trials on caffeine and endurance running performance. Per Chapter 3, the meta-analysis itself is a secondary source — it synthesizes 21 primary sources (the individual RCTs) rather than collecting new data of its own.

Applying CRAAP: Currency (a recent meta-analysis, appropriate for an active research area); Relevance (directly addresses the PICO question above); Authority (published, peer-reviewed sports science research); Accuracy (reports a specific, checkable effect size and p-value rather than a vague claim); Purpose (informing, not selling a supplement) — the source passes on all five.

Because this source is a systematic review of 21 RCTs with explicit inclusion criteria — not one author's own curated selection — Chapter 5's own narrative-vs-systematic distinction gives real reason to trust it more than a single cherry-picked study or a narrative blog summary would deserve.

This question is inherently quantitative — it asks "how much," measured in effect size and percentage improvement. A qualitative study (e.g. interviewing athletes about perceived exertion) could meaningfully complement this finding, but couldn't answer the core PICO question on its own — matching Chapter 6's own principle of matching method to question.

The 21 underlying studies are randomized controlled trials — real experiments, per Chapter 8's own comparison — genuinely well suited to this question specifically because it's a causal one ("does X cause a change in Y"), the exact real strength experiments have over surveys or observational studies.

Final synthesized answer: Based on a systematic review and meta-analysis of 21 randomized controlled trials, pre-exercise caffeine ingestion (3-9 mg/kg) is associated with a real, statistically significant improvement in endurance time to exhaustion (effect size g = 0.392, p < 0.001; mean improvement 3.2% ± 4.3%). The effect is genuine but shows substantial individual variability (range: -0.3% to 17.3%), meaning the real, honest answer is "caffeine improves average endurance performance in controlled trials, with a meaningfully different effect size for different individuals" — not a uniform guarantee for any one person.