NEW 2017 fresh paper "Assortative mating and couple similarity: Patterns, mechanisms, and consequences"

http://onlinelibrary.wiley.com/doi/10.1111/spc3.12337/abstract

from same 2005 author
Assortative Mating and Marital Quality in Newlyweds: A Couple-Centered Approach
http://www.apa.org/pubs/journals/releases/psp-882304.pdf

Page #19 of PDF whitepaper
Page #322 of magazine
"................
People may be attracted to those who have similar attitudes, values, and beliefs and even marry them (at least in part) on the basis of this similarity. However, once individuals are in a committed relationship, IT MAY BE PRIMARILY PERSONALITY SIMILARITY THAT INFLUENCES MARITAL HAPPINESS. This suggests that attitude and value similarity may play a different role in relationship development than personality similarity does. For example, whereas similarity in attitudes and values appears to be important early on in the relationship and may play an important role in relationship progression, personality similarity becomes more important as the relationship reaches greater commitment. Our empirical findings and this proposition are certainly consistent with "filter" or "process" theories of relationship development (e.g., Kerckhoff & Davis, 1962; Murstein, 1980) that hold that patterns of similarity and complementarity on different individual-difference domains play differential roles at different points in the relationship development process.
……………. FUTURE RESEARCH designed to better understand these underlying processes is needed.
.................................."

http://onlinedatingsoundbarrier.blogspot.com.ar/2010/03/latest-research.html
http://onlinedatingsoundbarrier.blogspot.com.ar/2012/02/top-45-scientific-papers-for-online.html
http://onlinedatingsoundbarrier.blogspot.com.ar/2010/05/sentimental-dynamics-accounting-for.html

Please see also another paper
Assortative Mating and Personality in Human Couples
http://onlinedatingsoundbarrier.blogspot.com.ar/2013/03/new-paper-assortative-mating-and.html

and
Contradictory information from eHarmony and PROOF of FRAUD from the papers they had published using the OBSOLETE NORMATIVE PERSONALITY TEST BIG FIVE.
http://onlinedatingsoundbarrier.blogspot.com.ar/2017/08/contradictory-information-from-eharmony.html
 
Online Dating sites have very big databases, in the range of 20,000,000 (twenty million) profiles, so the Big Five model or the HEXACO model are not enough for predictive purposes. That is why I suggest the 16PF5 test instead and another method to calculate similarity.

High precision in matching algorithms is precisely the key to open the door and leave the infancy of compatibility testing.
Without offering the NORMATIVE 16PF5 (or similar test measuring exactly the 16 personality factors) for serious dating, it will be impossible to innovate and revolutionize the Online Dating Industry.
 
The 3 milestone discoveries of the 2001 - 2010 decade for Theories of Romantic Relationships Development are:

I) Several studies showing contraceptive pills users make different mate choices, on average, compared to non-users.
"Only short-term but not long-term partner preferences tend to vary with the menstrual cycle"

II) People often report partner preferences that are not compatible with their choices in real life. (Behavioural recommender systems or other system that learns your preferences are useless)

III) What is important in attracting people to one another may not be important in making couples happy.
Compatibility is all about a high level on personality similarity between prospective mates for long term mating with commitment, and not meet other people with similar interests or political views.
 
At the paper  "Perceptions of Ideal and Former Partners' Personality and Similarity" 
The authors had written
".... mismatches in personality are a frequently mentioned cause for relationship break-up. If former partners indeed have dissimilar personalities, our findings underline how difficult it is for many people to select a mate with a similar personality, or, alternatively, how little value individuals put on finding a similar partner in terms of personality.
The present study's results, as well as the results found in previous studies (e.g., Eastwick & Finkel, 2008), may be used to educate people, especially singles, about what really matters in long-term relationships, for instance, similarity in personality, instead of complementarity."

The Online Dating Industry does not need a 10% improvement, a 50% improvement or a 100% improvement. It does need "a 100 times better improvement"
 
The 8 tips to innovate in the Online Dating Industry!
http://onlinedatingsoundbarrier.blogspot.com.ar/2013/12/the-8-tips-to-innovate-in-online-dating.html