Research Bites: Explicit vs Implicit Grammar Instruction

[note: this post has been updated based on suggestions from Dr. Nina Spada, one of the authors of the study]

Grammar is a divisive word. If you admit you teach grammar, you could be shunned in certain ELT circles. And even for those circles that do accept grammar, the debate still rages about whether it should be taught directly (explicitly) as it has in the past, or indirectly (implicitly), more in line with more modern or “post-modern” methods.

While the debate won’t easily be put to rest, a lot of evidence has come out against implicit grammar instruction as ineffective or less effective than explicit instruction. If you are still on the fence, this 2010 meta-analysis by Nina Spada and Yasuyo Tomita should help you make up your mind.


Spada, N., & Tomita, Y. (2010). Interactions between type of instruction and type of language feature: A Meta‐Analysis. Language learning, 60(2), 263-308.

Twitter Summary

Explicit more effective than implicit grammar instruction #ResearchBites

Introduction and Definitions

Spada and Tomita analyzed a total of 41 separate studies (in 30 publications) between 1990 and 2006. 63% of these studies were based on implicit grammar instruction. The authors calculated effect sizes for each study and compared each group’s average effect size to come to a conclusion about which type of instruction was more effective, on what type of linguistic features, and for how long. The authors categorized studied by instruction type, complexity, and type of knowledge based on the following definitions:

  • Instruction Type
    • Explicit instruction was defined as any instruction that involved rule explanation, language contrasting, and metalinguistic feedback.
    • Implicit instruction was defined as instruction that did not involve rules or attending to any form.
  • Complexity
    • There are numerous ways to measure complexity. The authors chose linguistic complexity based on the number of transformations a particular form had to go through.
    • Simple language features were those forms that included one transformation rule and one or two transformations.
      • An example would be article usage, tenses, plurals, etc.
    • Complex language features were those that involved multiple transformations.
      • Question formation, passive voice
  • Outcome Measures
    • Declarative knowledge, i.e. knowledge of rules, is knowledge measured by controlled tasks such as metalinguistic judgments (judging whether a sentence is correct or not), multiple-choice tests, scrambled sentences, and “constrained constructed responses” that ask learners to produce an utterance.
    • Implicit knowledge, i.e. the spontaneous ability to use a grammatical form, was measured by free writing, oral picture descriptions, information gaps.


The results indicated that explicit instruction had was more effective for both simple and complex language features. In addition, explicit instruction led to both greater explicit* and implicit knowledge. Finally, explicit instruction was also more effective in the long term (as measured by delayed post tests). One result that surprised the authors: the largest effect size in this study was of explicit instruction of complex language features on implicit knowledge (measured by “free constructed response” tasks). Implicit instruction only showed a medium effect size (some effectiveness) for simple language features on free tasks.


The authors point to a few caveats about their findings:

  • It is hard to tell if measures of implicit knowledge are really measuring spontaneous production or automatized declarative knowledge.
  • If they had looked at complexity in a different way (e.g. pedagogical complexity – how difficult it is to teach a feature), the results may have turned out differently
  • The number of studies they included that had delayed post tests were low. More research needs to use delayed post tests.
  • As Geoff Jordan pointed out in the comments, the study does not take into consideration the context of the explicit feedback, meaning whether it was included as part of a typical coursebook’s presentation and practice exercises or done in some other way.
    • Dr. Spada responded to this in an email: “To clarify, most of the studies included in the meta-analysis included instructional activities and exercises that were developed by the researchers but if I recall correctly, some of them also included exercises from ELT textbooks.  In any case, whatever the source of the instructional materials they were all coded in the same way – i.e. whether the instruction involved rule explanation, language contrasting, and metalinguistic feedback or not.”

Practical Implications

This article matches quite nicely the post I made a few weeks back about the power of being explicit. Being explicit about learning and language is clearly more beneficial than hoping learners will discover these things on their own. And just because grammar is taught explicitly doesn’t mean it is support for grammar translation, rule lectures, or grammar McNuggets. Rule explanation can come up quite organically in any class, from PPP to Dogme. And, any type of grammar can be made meaningful or fun. Implicit grammar instruction takes longer than explicit instruction to have even a medium effect. So, in my view, don’t beat around the bush. Get straight to the rules and then move on to what’s really important: using the language. As Dr. Spada pointed out to me, “…explicit attention to language form does not exclude attention to meaning/communication/content other than language.  Furthermore, most of the research investigating the effects of instruction on L2 learning indicates that a combination of language-based and meaning-based instructions works better than an exclusive focus on either one.”

*Originally, I used the term “declarative knowledge”. However, Dr. Spada pointed out in an email that “declarative” is often contrasted with “procedural”. In the article, they used the term “explicit”: “While declarative knowledge is considered to be the same as explicit knowledge this is not the case with procedural and implicit knowledge.   So while you are technically correct that we measured learners’ progress in terms of their declarative L2 knowledge and their implicit knowledge, we used explicit & implicit as the contrasting constructs for L2 knowledge when discussing the findings.”

9 thoughts on “Research Bites: Explicit vs Implicit Grammar Instruction

  1. But there are other ways of teaching which don’t fit neatly into either of the two paradigms described above. I almost never gave explicit grammar rules but I didn’t just sit there “hoping learners will discover these things on their own”. I was very active in making sure learners did work out which structure was appropriate in which circumstances.

    For example, if a learner should say “I marker’s blue” while holding a blue marker I’d represent the sentence on the board by a dash for each word like this: “- -‘s -“Then I’d point to the first dash and make a grimace or say “problem” and indicate they should change it. If the learner couldn’t supply “my”, I’d solicit the rest of the class and only if nobody could, would I give them the word “my”. Then I’d ask a second learner to hold up a different coloured marker and make the first learner face the second one and indicate that the first learner should speak to the second one. If they had problems producing “Your marker’s green”, I’d help them as for the first sentence. Then I’d turn the first learner to face me and have them point to the second learner and say “His marker’s green” (or “Her marker’s green” as appropriate”). And so on with the different Possessive Pronouns which I felt no need to name as such, and with different learners speaking.

    The example I’ve given is for low level learners, but I worked the same way with all levels: getting learners to produce the necessary structure and contrasting it with slightly different situations.

    • Anthony Schmidt says:

      Hi Glenys,

      Thanks for the comment. Of course, explicit and implicit are two ends of a continuum and teachers can mix the two to some degree. I enjoyed reading your description of how you may correct a simple yet complex language element salient. Based on the article’s operationalization of the “explicit instruction,” your activity would likely fall under explicit because “learners were directly asked to attend to particular forms and to try to arrive at metalinguistic generalizations on their own” (p. 273). I will say that I tend to use prompts when giving oral corrective feedback. For example, for an error like the one you mentioned, I would likely repeat it back with question-intonation. If the student did not understand, I would give some implicit feedback by giving alternative examples, such as “His marker’s blue,” “Her marker’s blue” – emphasis on the pronouns. Failing, that, I would give a direct, explicit correction and then explain why. Prompts and explicit feedback have been shown to be more effective than other types of feedback (See but I don’t always follow that.

  2. Penny Ur’s comment, in her ELT Oxford Journal article “Language-teaching method revisited” is really hard to beat. Even though the article is specifically concerned with TBLT rather than grammar as such, I still think her comment could have some relevance in the grammar teaching debate and in fact in any ELT debate that touches on method.

    “Language teaching should not be primarily based on a method but rather on a set of principles and procedures based on teachers’ practical situated experience, enriched by research, theory, and practice relevant to teaching and learning of any subject, as well as those relating to linguistics and applied linguistics.”

    As a front line teacher I unashamedly, energetically and explicitly teach grammar if and when the need arises. I do not however follow a grammatical syllabus which is maybe what caused the implicit/explicit grammar instruction debate in the first place.

    • Anthony Schmidt says:

      I think you are correct that the grammar syllabus may be at the heart of the debate. But, I do know some teacher who have sworn off grammar completely as if it would actually cause language learning to decline.

      That quote from Ur is great. Would you consider grammar instruction a method, a principle, or a procedure?

      • Hi Anthony,

        You’ve got me there! I can only talk, with any degree of certainty, about my own particular approach to grammar teaching and how it fits in with my overall teaching style. For some it looks like making it up as I go along, for others it’s teaching what the learners need when they need it.

        I teach grammar reactively, temporarily interrupting the real class to clarify some grammatical point only when and if the need arises. If one day I waltzed into one of my classes and gleefully announced that we were all going to look at some discrete grammar item or other, totally out of the blue, my students would look at me blankly and ask me “why?”, or worse still enquire if I was feeling OK.

        I realise that this approach is only possible as a result of a particular set of circumstances, the most important of which being the total absence of a course book in my classes. Reactive teaching is only possible when there is no obligation to follow a grammar syllabus or teach discrete grammar units pre-emptively.

  3. Hi Anthony,

    Despite your attempts to clarify what Spada & Tomita’s meta-survey does and doesn’t say, I think it’s worth stating that the survey attempts to compare 2 types of instruction. The authors used Norris and Ortega’s (2000) classification, where instruction was considered to be explicit if “rule explanation comprised part of the instruction” or “if learners were directly asked to attend to particular forms and to try to arrive at metalinguistic generalizations on their own”. So explicit instruction = “grammar rule explanation, L1/L2 contrasts and metalinguistic feedback”. Implicit instruction = “absence of rule presentation and directions to attend to particular forms”. Some examples of implicit instruction include input flood/high-frequency input, interaction, and recasts. Thus, none of the studies summarised in the meta-survey even considered the benefits of the type of presentation and practice of grammar found in most coursebooks. There is near-total agreement among scholars in the field of instructed SLA that such explicit instruction doesn’t work.

    So first, I’d just like to emphasise the point you make: explicit attention to grammar doesn’t mean basing a course on the presentation and practice of successive bits of pre-selected formal parts of the language. But, second, the caveats don’t stop there. The meta-survey looked at the effects of explicit and implicit instruction on the acquisition of simple and complex grammatical features in English. So

    1. That explicit instruction works better (for some kinds of learning) than implicit instruction, doesn’t say anything about how much explicit instruction a teacher should engage in.
    2. I can’t see anything in Spada and Tomita’s article (or Norris ant Ortega’s) to support your assertion that “implicit grammar instruction takes longer than explicit instruction”.
    3. I think the advice to “Get the rules out of the way early and focus on what’s really important: using the language” is based on a misinterpretation of the findings and is, in any case, bad advice.

    • Anthony Schmidt says:

      “Thus, none of the studies summarised in the meta-survey even considered the benefits of the type of presentation and practice of grammar found in most coursebooks.”

      When I read this study, I did not think once about coursebooks. I thought of “reactive” grammar teaching as the commenter above wrote, or otherwise more meaningful explicit grammar instruction than what simply going through coursebooks would provide. You said that “There is near-total agreement among scholars in the field of instructed SLA that such explicit instruction doesn’t work.” I’d love to read some empirical articles on this if you know of any.

      As for your other points

      2. On page 287, the authors state: “Thus, regardless of linguistic complexity, implicit instruction does not appear to have as significant an effect as explicit instruction. This may be because implicit instruction takes a longer time to be effective and none of the studies in this meta-analysis included more than 10 hr of instruction.” This doesn’t mean it takes longer in the classroom. I agree that I miswrote this and I will fix the mistake.

      3. The advice was my advice based on interpretation and experience. Why do you think it is bad?

      Explicit instruction is more effective in the contexts the study was investigating. Clearly grammar should be taught directly. However, rules are nothing without meaningful practice. So, I see explicit teaching as not only being more effective in terms of acquiring declarative knowledge and usage of a form, but also in facilitating more time in the usage of that form. That is, even if implicit grammar instruction is actually non-instruction or takes less instructional time, it seems there would be more work down the road in terms of corrective feedback and re-teaching of points which may have been somewhat avoided had the instruction been explicit in the first place. So, in my view, it is best to deal with as much as possible beforehand. Of course, there is nothing wrong with revisiting grammar points and feedback is necessary either way, but for the most part, I feel there is no need to “hide” the grammar

      In your view, does implicit language teaching take less time than explicit teaching? I suppose if you just skip grammar altogether, it would. Some advocate this. As a language learner myself, I wouldn’t appreciate that, especially with areas that I struggle with.

      Thanks for the comments and I will revise my post ASAP.

  4. Hi Anthony,

    Your interpretation that the study (of studies) was mostly concerned with “reactive” grammar teaching seems right to me. When I said “There is near-total agreement among scholars in the field of instructed SLA that such explicit instruction doesn’t work” I meant that SLA research refutes the view that learners learn the code in the order and manner in which coursebooks present it.

    I think your advice to “get the rules out of the way early on” goes against the view that learners benefit from occasional explicit instruction right the way through a course or a series of courses, and so it’s not a good idea to try to “front-load” this explicit work.

    I don’t say that implicit language teaching take less time than explicit teaching, just that I can’t see any good reason to suppose that the opposite is the case.

    • “I meant that SLA research refutes the view that learners learn the code in the order and manner in which coursebooks present it.”

      I wholeheartedly agree. Learners learn what they need when they are ready.

      “so it’s not a good idea to try to “front-load” this explicit work.”

      I didn’t mean front load grammar at the beginning of a course but in terms of reactive or planned teaching within a class, lesson or unit. In any case, to clarify my idea, I edited my original post.

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