Methodology

How the HMLI is computed.

Every claim on the HMLI is anchored to peer-reviewed research. Below is the source trail for the instruments, scoring, and benchmarks. The detailed internal methodology lives in our public strategy repository.

The instrument

The HMLI is a 30-item assessment that combines two of the strongest peer-reviewed instruments in the mental-load literature with one foundational qualitative framework.

Wayne et al. (2023) — Invisible Family Load Scale (IFLS-9). Nine items across three subscales — managerial, cognitive, emotional. 1-7 frequency Likert, past-month frame. Mixed-method 5-study validation. Journal of Business and Psychology 38(6):1159-1184. Won the 2024 Kanter Award. Source.
Catalano Weeks (2025) — the "71% study." N=3,000 US parents; 21 items across 7 domains (scheduling, childcare, social relationships, cleaning, food, finances, home maintenance); Cronbach α=0.92. Source of the famous 71% mother / 29% father split. European Sociological Review. Source.
Daminger (2019) — four-stage cognitive labor framework. Anticipate / identify / decide / monitor. Each HMLI item targets one of the four stages so the assessment captures the full cycle of cognitive labor, not only the visible execution. American Sociological Review. Source.

Scoring

The composite score (0-100) is the average of the seven Catalano-Weeks domain scores. Each domain score is the percentage of items where the user reports carrying the load mostly themselves (3 items per domain).

The IFLS-9 subscales are reported separately on a 0-100 scale, computed as the sum of Likert responses normalized to the maximum possible per subscale.

The dollar-cost translation uses the BLS American Time Use Survey 2023 and the 2024 Mother's Day Index ($140,315/yr methodology).

Cohort comparisons

Your "households like yours" comparison is computed from your demographic answers (number of adults, number of children, household income tier, country) against published benchmarks:

Dual-income with 2+ kids: 76% female mental-load share (Catalano Weeks 2025, median).
Dual-income with 1 child: 68% (Ciciolla & Luthar 2019).
Single-parent: 95%+ effective ceiling (estimated from Maternal Burnout literature).
Single-income (one stay-at-home): 79% (Catalano Weeks 2025).

Privacy & ethics

No PII required to complete the assessment.
No third-party tracking pixels on the assessment route.
Demographics are aggregated, never linked to email unless you opt in to Charter follow-up.
Aggregated benchmarks may inform our annual State of Household Intelligence report. Individual responses, never.
One-click delete-my-data link on the result page and every follow-up email.
This is not a clinical instrument. If your score correlates with persistent burnout, please consult a licensed therapist.

All sources

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