PBL-taught Iranian EFL learners achieved significantly higher vocabulary recall (total post-test) than conventionally taught learners¶

Claim · All claims
Evidence · 1 study · causal r2 · q3
Currency · newest study 2015 · checked against its sources 2026-11-01 (automated, 1 of 1 entry) · not reviewed by a person

Subclaims¶

Reading the evidence codes

q is the design tier, i the impact, n the sample, and the kind with its r the rigour judged within that kind: what each code means.

This claim: no standardized effect is recorded in observations/ for it yet, so no benchmark reading is possible.

q3 i? The experimental group taught with PBL had a significantly higher total post-test mean score than the control group at the 99% confidence level. → Shafaei 2015

Evidence¶

Shafaei 2015¶

Shafaei, A., & Abdul Rahim, H. (2015). Does project-based learning enhance Iranian EFL learners' vocabulary recall and retention? Iranian Journal of Language Teaching Research, 3(2), 83-99. https://www.urmia.ac.ir/ijltr

q3 · i? · causal · r2

Semi-experimental study with 40 EFL learners aged 16-18 in Rasht, Iran, randomly divided into experimental (n=20, PBL) and control (n=20, conventional) groups; post-test means were 28.15 vs 25.30 out of 30, and the article reports a statistically significant total post-test difference with no effect size printed.

"Results of the t-statistics reveal that the experimental group had a significantly higher total post-test mean score than the control group. This shows that PBL significantly improved Iranian EFL learners' vocabulary recall rate at %99 level of confidence."

Discussion¶

Learner Variables¶

Long-Term Memory — outcome: instruction changes it

On a delayed delayed-post-test covering all 30 items, the PBL group (mean 23.80) outperformed the control group (mean 17.15) — possibly the same claim (merge candidate)
PBL-taught learners showed significantly higher vocabulary retention on delayed post-tests in all modules except module 3 — related
Authentic problem-based vocabulary tasks improve immediate vocabulary recall of intermediate Iranian EFL learners compared with conventional input-based tasks — possibly the same claim (merge candidate)
The PBL advantage over the conventional method held for modules with more adjectives but not for the noun-heavy modules 3 and 5 on recall — a narrower finding that bears on this claim
Experimental and control groups were homogeneous in idiom knowledge before treatment — related

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