Published 12 October 2026 · 6 min read

What actually predicts a happy relationship

Compatibility is one of the most searched words in astrology. It's a fair question: will this work? Science has been asking it too, with surveys of thousands of couples, and the answer is more hopeful than any star chart.

What doesn't predict much

Large studies have looked for links between Sun signs and who marries or divorces whom. One analysis of around ten million marriages in England and Wales found no meaningful pattern. That doesn't make astrology useless as a language for talking about differences, but it does mean your signs aren't a verdict on your relationship.

More surprising: being similar in personality also matters less than people expect. Couples who score alike on the Big Five traits aren't much happier than couples who score differently. Opposites don't especially attract, but they don't doom each other either.

What predicts more: who each of you is

Personality does matter, just not as a match. What predicts satisfaction is each partner's own traits. People who are emotionally steady, warm and reliable tend to have happier relationships, whoever they're with. The effect isn't huge, but it shows up across many studies and countries.

That's good news, because these are things you can work on. Nobody can change their Sun sign. Anybody can practise answering kindly when they're stressed.

What predicts most: how you treat each other

In 2020, a team of researchers pooled data from 43 long-term studies of more than 11,000 couples and asked a machine-learning model to find the best predictors of relationship quality. The top ones weren't about either person on their own. They were about the relationship itself:

Feeling that your partner is committed to you.
Appreciation and gratitude.
A satisfying sex life, for couples where that matters.
Feeling that your partner is satisfied too.
Little conflict, or conflict that gets repaired.

In other words, the best predictor of a good relationship is what you do together, day after day. Small, repeated things: saying thank you, turning toward each other when one of you wants attention, and making up after a fight.

Repair beats perfection

Every couple argues. What separates lasting couples is often how quickly they repair: a joke that breaks the tension, an apology, a hand on the shoulder. Research on couples in conflict suggests that happy partners aren't the ones who never fight, but the ones who soften the start of hard talks and accept attempts to make up.

The stars set the scene, psychology explains the pattern, and how you treat each other writes the story.

So how do we score compatibility?

Our compatibility reports show many lenses side by side, from astrology and the Chinese zodiac to the Big Five and attachment styles. Each one is labelled by how much evidence stands behind it. The research-based lenses carry the most weight in the advice, and the traditional ones are there for reflection and fun.

The part we're proudest of is the Bond Check: a short set of questions about appreciation, trust, commitment, repair and fun, the things the research says matter most. You can take it together and see where you agree.

Try the Bond Check →

If your signs say you clash, don't panic. If they say you're a perfect match, don't relax too much either. Either way, the most useful thing you can do tonight is notice one thing your partner did right, and tell them.

Sources

Joel, S., et al. (2020). Machine learning uncovers the most robust self-report predictors of relationship quality across 43 longitudinal couples studies. PNAS, 117(32).
Malouff, J. M., et al. (2010). The Five-Factor Model of personality and relationship satisfaction of intimate partners: A meta-analysis. Journal of Research in Personality, 44(1).
Dyrenforth, P. S., et al. (2010). Predicting relationship and life satisfaction from personality in nationally representative samples from three countries. JPSP, 99(4).
Voas, D. (2007). Ten million marriages: A test of astrological 'love signs'.
Gottman, J. M., & Levenson, R. W. (1999). What predicts change in marital interaction over time?