Interactions Between Type of Instruction and Type of Language Feature: A Meta-Analysis

41 studies

Learners of English as a second or foreign language across the included studies

Tests the most common defence of implicit instruction - that explicit teaching helps only with simple rules, while complex features must be acquired implicitly. Target features were classified simple or complex by the number of criteria needed to arrive at the correct form; treatments were classified explicit or implicit following Norris & Ortega. The important design choice is that outcomes are separated into CONTROLLED knowledge and SPONTANEOUS USE, which is the distinction that usually collapses effect sizes.

Larger effect sizes for explicit over implicit instruction for BOTH simple and complex grammatical features - so the "complex features need implicit instruction" defence is not supported. Explicit instruction contributed positively not only to learners' controlled knowledge but also to their SPONTANEOUS USE of both complex and simple forms. That second finding is the strongest thing in this cluster, because spontaneous use is the outcome closest to actually speaking the language and the one on which effect sizes normally shrink.

Low as a threat to the pooled comparisons; learners are assigned to instructional conditions within studies.

Directionally consistent with Norris & Ortega, Goo et al. and Kang et al. on explicit over implicit. The specific simple/complex moderation test has not been independently repeated.