Effectiveness of L2 Instruction: A Research Synthesis and Quantitative Meta-analysis

Author: John M. Norris, Lourdes Ortega · Type: academic · Status: draft · URL: https://onlinelibrary.wiley.com/doi/abs/10.1111/0023-8333.00136

Licence: Language Learning 50(3), 2000 (Wiley); abstract openly indexed and quotable; full text paywalled

Summary

The classic meta-analysis of L2 instruction effectiveness, synthesizing experimental studies from 1980-1998 (49 unique samples). Focused L2 instruction produces large gains, explicit instruction types outperform implicit types, and instructional effects are durable over time. A later replication and extension (Goo et al. 2015, covering 34 studies including 23 newer ones) reached the same conclusion that explicit instruction beats implicit. This is the core evidence legitimizing Immersive’s explicit contrastive grammar notes as a feature grounded in the meta-analytic record, against the popular assumption that grammar study is obsolete and pure exposure suffices.

Insights

• Explicit instruction is more effective than implicit instruction in L2 learning, and focused instruction produces large gains, across 49 experimental samples from 1980-1998. (high, draft) grammar instruction meta-analysis explicit instruction

  focused L2 instruction results in large target-oriented gains, that explicit types of instruction are more effective than implicit types — Abstract

• The benefits of L2 instruction are durable, persisting on delayed measures rather than washing out. (high, draft) grammar instruction retention meta-analysis

  Further findings suggest that the effectiveness of L2 instruction is durable — Abstract

• The explicit-beats-implicit finding was reconfirmed by a 2015 updated meta-analysis (Goo et al.) adding 23 studies published 1999-2011 to the original sample. (medium, draft) grammar instruction explicit instruction replication

  Paraphrase: Goo, Granena, Yilmaz and Novella (2015) meta-analyzed 34 explicit-versus-implicit comparisons, 11 from Norris and Ortega plus 23 newer studies, and again found explicit instruction more effective. — Follow-up literature (Goo et al. 2015, revisiting this study)