This is one of the most pervasive statistical misunderstandings shared online today. The quick answer is no, it does not. You should live together with your partner before getting married.
History of the Living Together Before Marriage Statistic
Let's start by talking about the history of this statistic. In the 1980s researchers explored how people who lived together before marriage faired in their resulting marriages. They did find this behavior to be correlated with increased risk for divorce compared to people who lived together after getting married.
At the time, premarital cohabitation was a non-normative behavior. People who lived together before being married were fundamentally different from the rest of the population. This also means that characteristics of people who lived together before marriage may have contributed to their divorce risk -- it wasn't that living together was, itself, problematic. Rather, people selecting into premarital cohabitation also were more likely to be okay with divorce or had other kinds of behaviors/personality traits that corresponded with worse marital outcomes.
In addition, when comparing premarital cohabiters to direct marriers, or people who live together before marriage to those who wait to live together until they are married, there is a confounding factor of religion. People who are more religious are both more likely to wait to live together until marriage, and are less likely to divorce. So, on its face at the time, it appeared that premarital cohabitation may have been a cause of marital dissolution, divorce, or poor marital outcomes more broadly defined, on its own.
Challenging Our Understanding
In the 1990s, this assumption was challenged. People were increasingly more likely to premaritally cohabitate, thus, the behavior was becoming a more normative experience. Even with this shift in the behavior becoming more normative, it was still associated with poorer relationship outcomes, such as decreased relationship satisfaction or increased marital instability.
In the early 2000s, researchers wanted to explore the self-selection mechanism that had previously been identified - what is it about people who choose to live together before marriage that sets them up for poorer marital outcomes? Researchers Stanley, Rhoades, and Markman determined there were two groups of people who live together before marriage that they termed "sliders" and "deciders".
The difference between the two groups can be summarized by whether or not a couple had a discussion about the implications of moving in together on the state of the relationship. If a couple discussed the future of their relationship before they moved in together, they were deciders. These are the types of people that are naturally going to talk about transitions in the relationship together, meaning, they engage in relationship talk. They actively work to reduce the amount of uncertainty they might have about themselves, their partner, and the relationship through communicating together somewhat regularly.
Sliders, on the other hand, may fall victim to something called "relationship inertia", where they fall into the next phases of a relationship without that explicit discussion. Perhaps they found themselves living together as one partner moved their belongings in bit by bit. Maybe their leases were up and they felt like they spent so much time together that they may as well save on rent by living together. No matter what the reason for living together, they didn't explicitly discuss the future of the relationship before moving-in together. Before they know it, they are engaged, and then they are married, and then they are having kids - once the ball is in motion, it just keeps moving without intention.
In part, this can be attributed to the sunk cost fallacy - you've invested a lot of time into the relationship, perhaps have invested a lot of money into the relationship. Leaving it will mean you have to start over and re-invest in a new relationship. The process of starting over is more daunting than just moving forward in the relationship -- even if you aren't compatible for success, or are actively struggling together.
From a communication perspective, sliding into living together without explicit relationship talk sets the relationship up for increased risk of uncertainty. Uncertainty is a negative experience in romantic relationship that stems from simply not knowing. Relational uncertainty can be about a person's own role in the relationship, about what their partner feels about the relationship, or about where the relationship is going. For sliders, uncertainty may arise when partners haven't consciously discussed whether marriage is in their future. For example, one partner may have perceived living together as a convenient move, while the other saw it as a compatibility test for marriage - now one partner is expecting a ring and the other doesn't even know.
In one study published in 2014, researchers identified twelve sources of relationship uncertainty specific to people who are cohabiting without formalized plans for marriage. The sources of uncertainty included:
Relationship sustainability (will my relationship last?)
Relationship trust (cheating concerns)
Relationship compatibility (Is there someone better out there? Is my partner the right one?)
Relationship steps (concerns related to the progression of the relationship, like marriage)
Relationship norms (how much time to spend together, or equitability of chore distribution)
Personal growth (concern around individual goal achievement like schooling or a career)
Family planning (do we want children and how many children do we want)
Communication (differences in communication style that are frustrating, an unwillingness to talk about feelings)
Social network issues (friends or family don't like their partner, difficulty fitting in with friends or family)
Finances (spending habits or debts)
Sexual issues (frequency and quality of sex)
Health and well-being (concerns about depression, or substance abuse)
When the researchers assessed the overlap in concerns expressed by each partner in these relationships, they found that 86% of cohabiting couples had no or very minor overlap in their concerns about the relationships, with only 11% having a moderate amount of overlap, and one couple in their study reporting exactly the same concerns. This provides evidence that couples who slide into cohabitation together are less likely to talk about relationship concerns. Each partner in this study had their own uncertainty within and about the relationship that remain unaddressed.
What this means for you
We would all benefit from more relationship talk. It doesn't matter who you are, what phase of a relationship you are in, how ready you are to progress in your relationship (or not), you need to talk with your partner about your relationship.
Set aside regular, recurring time to check in with one another. If you aren't sure what to talk about together, consider buying a pack of Foundational Conversation Starter Cards that provide 200 prompts to talk about with your partner. Even if you think you know what your partner's answer will be, give them space to share something you weren't expecting. Relationship talk shouldn't be a box you check to earn living together, it should be an ongoing expectation of cultivating a healthy relationship.
Referenced
Bumpass, L. L., & Sweet, J. A. (1989). National estimates of cohabitation. Demography, 26(4), 615-625.
Dush, C. M. K., Cohan, C. L., & Amato, P. R. (2003). The relationship between cohabitation and marital quality and stability: Change across cohorts?. Journal of marriage and family, 65(3), 539-549.
Stanley, S. M., Rhoades, G. K., & Markman, H. J. (2006). Sliding versus deciding: Inertia and the premarital cohabitation effect. Family relations, 55(4), 499-509.
Steuber, K. R., Priem, J. S., Scharp, K. M., & Thomas, L. (2014). The content of relational uncertainty in non-engaged cohabiting relationships. Journal of Applied Communication Research, 42(1), 107-123.