What to do, in what order, with the evidence behind every step.
| ★★★★★ | Large sample (n=1,000+) or meta-analysis/cross-cultural, peer-reviewed in a top journal, replicated by other studies, minimal confounds |
| ★★★★★ | Solid sample (n=200–1,000) or strong theoretical model built on multiple studies, peer-reviewed, some replication or wide citation |
| ★★★★★ | Moderate sample (n=50–200), peer-reviewed, single study, no known replication yet, or minor methodological limitations (e.g. self-report only, WEIRD sample) |
| ★★★★★ | Small sample (n<50), preprint or lower-tier journal, notable confounds, correlational only where causation is implied |
| ★★★★★ | Very small/weak sample, not peer-reviewed, outdated methodology, or contradicted by later research. Flag for possible removal |
The sidebar filter is a minimum, not an exact match: picking three stars returns everything rated three or better, and only one level can be active at a time. The bars under “Library at a glance” above still show the exact distribution.
Which step a study gives advice for. Attraction covers changes to the man himself.
| Behaviour | Measured on a real app or in the field: matches, messages, numbers given. |
| Ratings | People judging profiles, photos or written scenarios. |
| Survey | What people say about themselves. |
| Review | A meta-analysis, review or book that pulls many studies together. |
| Mixed | A study that weakens or qualifies the advice. |
Behaviour is the strongest support for advice. A rating or survey shows what people think, which doesn't always match what they do.
| Contradicts | Same question, comparable population, opposite answer. One of them is probably wrong, or something unmeasured explains the difference. |
| Tension | Looks like a clash, but the scope differs: a different stage, outcome or population, or what people say versus what they do. Usually both are right, and the pair shows when each applies. |
Every entry is a plain-language summary of someone else's research, linked to the original. Read the original before relying on a number. This library is for education. It isn't medical, psychological or legal advice. Sources were last checked in October 2026.