The Big Picture of Relationship Satisfaction Research
"What makes romantic relationships succeed?" is one of the most extensively studied questions in psychology. Since the 1970s, thousands of studies have accumulated, and their findings have been integrated through multiple meta-analyses.
Le et al. (2010) conducted a meta-analysis synthesizing 137 studies (over 33,000 participants), ranking predictors of relationship satisfaction by effect size. Additionally, Karney & Bradbury (1995)'s Vulnerability-Stress-Adaptation Model proposed three categories of factors determining relationship quality (individual vulnerabilities, external stressors, and adaptive processes) and remains widely referenced today.
This article integrates these bodies of research and explains the factors determining relationship satisfaction in order of "magnitude of influence." To state the conclusion upfront: the most important factor is "communication quality," followed by "personality trait compatibility," and then "joint coping ability with external stress."
Rank 1: Communication Quality
Gottman's (1994) 40 years of research and Lavner & Bradbury's (2010) longitudinal studies consistently demonstrate that communication quality is the strongest predictor of relationship satisfaction.
Constructive communication: Openly discussing problems and striving to understand each other's perspectives. Dialogue patterns like "Tell me how you feel" and "This is how I feel." The effect size is r = .45-.55, remarkably large, possessing stronger predictive power than any other factor.
Destructive communication: Criticism, contempt, defensiveness, and stonewalling (Gottman's Four Horsemen). Couples with high frequencies of these behaviors have separation rates exceeding 80% within five years.
Everyday positive interactions: The quality of daily exchanges during non-problematic times also matters. Showing interest in your partner's stories, performing small kindnesses, verbalizing gratitude. Gottman calls this the "Emotional Bank Account," explaining that daily "deposits" make "withdrawals" possible during crises.
In relation to the Big Five, people high in agreeableness tend toward constructive communication, while those high in neuroticism tend to fall into destructive communication patterns.
Rank 2: Personality Trait Compatibility
Malouff et al. (2010)'s meta-analysis demonstrated that Big Five personality traits are significant predictors of relationship satisfaction. The effect size is r = .20-.30, second in influence only to communication.
Individual trait levels: The higher a partner's agreeableness (r = .28), emotional stability (r = .26), and conscientiousness (r = .20), the higher one's own relationship satisfaction. In other words, a clear personality profile of a "good partner" exists.
Couple similarity: Personality similarity is also an independent predictor. Similarity in traits directly linked to values (conscientiousness, agreeableness) is particularly important, reducing daily friction.
Limited role of complementarity: For extraversion, a combination where "one is somewhat higher" may sometimes be optimal rather than perfect matching. However, for the other four factors, similarity is consistently advantageous.
This site's compatibility assessment is a tool that quantifies this "personality trait compatibility." Big Five similarity scores possess predictive power explaining approximately 20-30% of relationship satisfaction.
Rank 3: External Stress and Joint Coping
Bodenmann's (2005) Stress-Divorce Model explains the mechanism by which external stressors (financial difficulties, work pressure, health problems, childcare burden) reduce relationship satisfaction.
What matters is not the stress itself but the quality of "dyadic coping" - jointly managing stress. Couples who can recognize their partner's stress and provide both emotional support ("That must have been tough") and practical support ("I'll cook tonight") can maintain relationship satisfaction even under high stress. Related books can also be found at related books (Amazon).
Bodenmann et al. (2006) reported that couples with high dyadic coping skills had significantly higher relationship satisfaction after five years and lower separation rates. The effect size is r = .30-.40, possessing predictive power equal to or greater than personality traits.
In relation to the Big Five, people high in conscientiousness tend to provide practical support more readily, while those high in agreeableness tend to provide emotional support more easily. People high in neuroticism tend to be overwhelmed by their own stress and often fall short in supporting their partner.
Rank 4: Commitment and Investment
Rusbult's (1983) Investment Model demonstrated that commitment to a relationship is determined by three factors: (1) satisfaction (Am I satisfied with this relationship?), (2) quality of alternatives (Are there better options available?), and (3) investment size (How much have I invested in this relationship?).
Le & Agnew's (2003) meta-analysis confirmed that commitment is the strongest predictor of relationship persistence (r = .47). In other words, the strength of the will to "continue this relationship" most powerfully predicts whether the relationship actually endures.
Commitment is also related to personality traits. People high in conscientiousness tend strongly to maintain relationships once committed, adopting a "let's overcome this" attitude when facing difficulties. Conversely, people extremely high in openness may find that curiosity about new possibilities elevates their evaluation of "quality of alternatives," potentially destabilizing commitment.
Rank 5: Sexual Satisfaction
McNulty, Wenner & Fisher's (2016) longitudinal study demonstrated that sexual satisfaction is an independent predictor of relationship satisfaction. The effect size is r = .20-.35, comparable in influence to personality traits.
An important finding is that sexual satisfaction depends more on "quality" and "alignment" than on "frequency." When there are large discrepancies between partners in the frequency or content of sexual desire, this leads to dissatisfaction with the relationship as a whole.
In relation to the Big Five, people high in openness are proactive about sexual exploration, and those high in extraversion are open about sexual communication. People high in neuroticism tend to feel anxiety even in sexual situations, and performance anxiety can reduce sexual satisfaction.
While this site does not directly assess sexual satisfaction, Big Five similarity (particularly in openness and extraversion) can be considered an indirect indicator of sexual compatibility.
An Integrated Perspective - What Matters Most
Integrating 50 years of research reveals that relationship satisfaction is the composite result of the following factors.
Factors that cannot be changed: Personality traits (can change gradually), attachment style (takes time to change), age difference (fixed). These set the relationship's baseline as "initial conditions."
Factors that can be changed: Communication skills (learnable), joint coping ability (trainable), commitment (a volitional choice), everyday positive behaviors (can become habitual). These update relationship quality daily as "processes."
This site's compatibility assessment evaluates part of the "unchangeable factors" (personality trait compatibility). A high score means "a good starting point," but relationships do not automatically succeed without effort on the "changeable factors."
Conversely, even with a low score, it is entirely possible to build a highly satisfying relationship by consciously improving the "changeable factors." What research consistently shows is that "daily behavioral choices" have greater influence on long-term relationship quality than "personality compatibility." A compatibility assessment is a starting point, not a destination.