{
  "schema_version": 1,
  "id": "woop-mcii-goal-attainment-meta-analysis-2021",
  "canonical_url": "https://brali-lifeos.github.io/evidence/woop-mcii-goal-attainment-meta-analysis-2021/",
  "json_url": "https://brali-lifeos.github.io/evidence/woop-mcii-goal-attainment-meta-analysis-2021/index.json",
  "decision": "support-existing",
  "decision_label": "Supports existing guidance",
  "reviewed_at": "2026-09-09",
  "reviewed_by": "Brali Evidence Reviewer",
  "source": {
    "title": "A Meta-Analysis of the Effects of Mental Contrasting With Implementation Intentions on Goal Attainment",
    "url": "https://www.frontiersin.org/journals/psychology/articles/10.3389/fpsyg.2021.565202/full",
    "type": "systematic-review-meta-analysis",
    "doi": "10.3389/fpsyg.2021.565202",
    "citation_text": "Wang G, Wang Y, Gai X. Frontiers in Psychology. 2021;12:565202.",
    "study_design": "Random-effects meta-analysis of 21 empirical articles contributing 24 independent MCII effect sizes across field interventions and goal domains, with 15,907 participants in total.",
    "population": "Children, college students and adults across academic, health, relationship and personal goal contexts represented in the included intervention studies. The corpus was heterogeneous and was dominated numerically by two very large MOOC samples.",
    "intervention_or_exposure": "Mental contrasting with implementation intentions: identify a desired future and an obstacle in reality, then form an if-obstacle-then-behavior plan. Delivery varied between experimenter-led and document-based interventions.",
    "outcomes": [
      "Goal attainment across included studies"
    ]
  },
  "supported_claim": "Across the included field-intervention studies, mental contrasting with implementation intentions was associated with a small-to-medium average improvement in goal attainment. The pooled random-effects estimate was Hedges' g=0.336, while publication-bias adjustment produced a smaller estimate. This supports WOOP/MCII as a bounded self-regulation option for feasible goals, not as a guarantee of individual goal success.",
  "unsupported_or_overstated_claims": [
    "WOOP guarantees that a person will achieve a goal.",
    "The pooled effect size applies to every person, goal domain or delivery format.",
    "WOOP is always better than mental contrasting or implementation intentions used separately.",
    "A document or self-guided WOOP exercise is as effective as an experimenter-led intervention.",
    "The meta-analysis establishes a clinically meaningful treatment effect.",
    "The study proves that one fixed WOOP script is optimal."
  ],
  "limitations": [
    "The included studies were heterogeneous in population, goal domain, intervention delivery and outcome measurement.",
    "The meta-analysis reported medium heterogeneity and mixed publication-bias diagnostics; trim-and-fill yielded a smaller adjusted estimate.",
    "Two very large MOOC studies accounted for most participants and were excluded from moderator analyses because of their numerical dominance.",
    "The number of studies was limited for moderator inference, and the authors explicitly called for additional studies.",
    "An average standardized effect cannot predict whether the protocol will help one individual with one goal."
  ],
  "target_hack_ids": [
    "woop-goal-planner"
  ],
  "target_protocol_ids": [
    "brali:woop-goal-planner"
  ],
  "risk_flags": [],
  "notes": "Editorial outcome: retain WOOP as reviewed practical self-regulation guidance for meaningful, reasonably feasible goals. Keep the user-visible wording focused on the obstacle-to-if-then planning process and an observable attempt, not a promise of goal attainment or an advertised effect size."
}