eHarmony Method – How does it work?

Ask the Research Doctor a question.

Moderators: shawnski, jdenver, rogerwimmer

Forum rules
How do you ask the Research Doctor a question?

Just click on "New Topic" below and then type your question to me. Please put in a Subject and then ask your question in the body.

Your question is submitted annonymously unless you include your name.

Click "Submit" and then check back to find Dr. Wimmer's answer to your question.

If you wish to have a private answer to a question (not posted in the forum), please include your email address. Dr. Wimmer will send your answer directly to you.

Dr. Wimmer maintains an Archive of questions from the forum. Go to and click on "The Research Doctor Archive" link.
Post Reply
User avatar
Posts: 197
Joined: Mon Sep 28, 2009 12:40 pm

eHarmony Method – How does it work?

Post by rogerwimmer » Wed Mar 31, 2010 12:57 pm

Doc: My question is about eHarmony, the website for finding dates. On the company's website, it says: "Our patented Compatibility Matching System® pre-screens matches for you based on deep levels of compatibility." I know each person fills out a questionnaire, but do you know how the "matching" part of it works? Thanks in advance. - Anonymous


Anon: I have seen commercials for eHarmony, but didn't know anything about it until I read several things on the Internet. I want to apologize for taking a few days to answer your question, but I spent many hours reading articles about eHarmony. However, I don't consider myself as an expert on eHarmony. My comments are based only on the information I read and I'll be happy to adjust my comments upon learning additional information. On to your question . . .

So that all readers are on the same level of understanding about eHarmony, this is a statement from the company's website:

eHarmony is the first service within the online dating industry to use a scientific approach to matching highly compatible singles. eHarmony's matching is based on using its 29 DIMENSIONS® model to match couples based on features of compatibility found in thousands of successful relationships.

One of the first things I noticed, and you included in your question, is this item on eHarmony's home page:

eHarmony Compatibility Matching System®
Protected by U.S. Pat. No. 6,735,568

The Matching System is protected by a patent? Patent for what? I put this aside for a moment and will do the same thing now. I'll get to the patent in a moment.

In order to answer your question (How does it work?), I needed to find an explanation of the methodology. What I found is that a description of the methodology is not available. Why not? Well, the founder of the company, Dr. Neil Clark Warren, a clinical psychologist, not an M.D., states in many references that the company's methodology is proprietary. As far as I know, the eHarmony methodology has not been reviewed by a competent panel of researchers ("panel of peers," as it's called) and I thought I might have a difficult time finding out how the company's procedure "works," as you ask. But I forged ahead.

With no access to a description of eHarmony's methodology, the only thing I can do is take a guess. If I were in charge of the eHarmony methodology, I would follow the guideline of Ockham's Razor, which states (paraphrase) that, "The simplest approach is always the best." With simplicity as a guide, I would probably match people using Pearson Product-Moment Correlation, known simply as "correlation," and/or Factor Analysis, a multivariate statistic that, in simple terms, places items (variables) into groups or categories called Factors. (See note at end about correlation.)

There Must be More
As I continued my reading, I thought there must be more information available about the eHarmony patent. Guess what? I found many things, and a summary of the patent claims virtually explains the eHarmony methodology. Dr. Neil Clark Warren and other people at eHarmony may consider their methodology as proprietary, but virtually all of the steps are contained in the patent summary. Anyone with an understanding of research and statistics can immediately identify the methodology from only the patent summary.

I haven't read the entire patent. Life is too short for that. However, what I found is contained in the next section.

eHarmony Methodology from the company's Patent
A website called Patent Storm has this information:

US Patent 6735568 - Method and system for identifying people who are likely to have a successful relationship. Issued May 11, 2004

A summary of eHarmony's patent claims is shown on the Patent Storm page. A part of that summary is shown below. I include an explanation of what each claim actually means after each claim.

11. A method to be performed by a computer for operating a matching service, comprising:

receiving a plurality of surveys completed by different individuals, each survey including a plurality of inquiries into matters which are relevant to each individual forming relationships with other people, at least a portion of the inquiries having answers that are associated with a number; [What? This means that the company collects questionnaires from many (plurality) people. The questionnaire includes many (plurality) questions, reportedly 430 questions. Some of the questions ("a portion of the inquires") are used to compute a "number," which I assume is the "Satisfaction Index" mentioned later. Nothing fancy, just simple statistics and research procedures.]

performing a factor analysis on the answers to the inquiries to identify a plurality of factors, each factor corresponding to a function of one or more variables representing the inquiries; [What? This means that each questionnaire is analyzed via the multivariate statistic, factor analysis (identified later as Principal Components factor analysis) to identify the "29 Dimensions® of Compatibility" the company uses to match people. (Note: Principal Components factor analysis assumes that the factors, called dimensions by eHarmony, in the factor analysis are not related to each other—that the 29 dimensions are unique and distinct from the other factors in the analysis. One more thing...each person will have a "factor score" for each of the 29 factors (dimensions). In brief, a factor score is a summary score, where a person's score for all the variables in a factor (dimension) are added together (linear combination). In statistics, the factor scores are called eigenvalues. Nothing fancy, just a simple factor analysis.]

generating a satisfaction index that approximates the satisfaction that a first candidate has in the relationships that the first candidate forms with others; and [What? Of the 430 questions in the questionnaire, some are used to develop the "Satisfaction Index." I obviously don't know what these questions are, but I assume they relate to a person's "happiness with their current situation," or a "satisfaction with their life and job," and so on. The company simply adds together the numerical answers (ratings of some kind) for the "satisfaction questions" to produce the Satisfaction Index. Nothing fancy, just simple statistics.]

matching the first candidate to a second candidate based upon the satisfaction index and based upon differences between the value of at least one factor for the first candidate and the value of at least one factor for the second candidate. [What? The Satisfaction Index and one factor score from a person's questionnaire are compared to other people in the database. This is probably done with simple correlation. Nothing fancy, just simple statistics.]

12. The method of claim 11, wherein the factor analysis is a principal component analysis. [What? There it is. The company identifies the primary statistic used to analyze questionnaires. Nothing fancy, just a simple multivariate procedure.]

13. The method of claim 11, further comprising: selecting the factors that most highly predict satisfaction in a relationship. [What? The company uses "29 Dimensions of Compatibility" to match people, but not everyone will rate or score all the questions in each factor the same way. For example, a person's factor analysis may show that only 10 of the 29 dimensions are important. My guess is that the company probably computes a correlation between the factor scores of one person to all other people in the database. In addition, they also use linear regression, which is mentioned in the next claim. Nothing fancy, just simple statistics.]

14. The method of claim 11, wherein selecting the factors includes performing a linear regression on the factors and the satisfaction index. [What? A linear regression just compares one variable (factor scores) to another (Satisfaction Index). Nothing fancy, just simple statistics.]

15. The method of claim 11, wherein selecting the factors includes performing a correlation analysis on the factors and the satisfaction index. [What? There it is. The company uses correlation to compare the factor scores and Satisfaction Index from one person to the other people in the database. Nothing fancy, just simple statistics.]

Ah ha! My guess was correct. The eHarmony patent states that the methodology involves factor analysis, correlation, and linear regression—nothing fancy, just simple statistics. The problem I have is understanding why the company would receive a patent for this procedure. It's comparable to me receiving a patent for something called, "A Method to Compute Students' Grades in a Classroom Setting," and I go on to explain how to add together scores on tests and quizzes (and other things) to get a total score and then say something like . . .An "A" grade is designated for students who receive 90-100 total points; a "B" grade is designated for 80-89 points, a "C" grade is designated 70-79 points, and so on. The eHarmony patent seems a bit silly and it's not clear to me why the U.S. Patent Office would grant a patent for a simple statistical methodology.

eHarmony Methodology in Simple Terms
I would like to explain the ]eHarmony methodology in another way in the event some readers don't understand the statistics. From the patent information, here is what the company does:

The Questionnaire: I assume that eHarmony researchers (or whomever) followed the typical steps used in research to develop a questionnaire such as the one used to match people. Initially, the company probably tested 1,000 or more questions to determine which were good and which were bad. After a number of tests, they reduced to the number of questions to 430, most of which are used for the "29 Dimensions of Compatibility," and a few questions for the Satisfaction Index.

Assuming that the questionnaire does include 430 questions, my guess is that each of the "29 Dimensions of Compatibility" is represented by 14 questions, which means that about 24 questions are used for the Satisfaction Index. Is that clear? Try this...when a factor analysis is computed on a set of variables, the statistic identifies variables that relate to a similar concept. In the eHarmony procedure, I would imagine that the factors/dimensions are labeled something like, "Marriage," "Career," "Children," "Spending Habits," and so on.

Each of the factors, as I mentioned, is represented by about 14 questions, and about 50% would have a negative slant toward the concept ("Marriage") and 50% with a positive slant toward the concept. A person's answers to all 14 "Marriage" related questions are added together to produce the person's Factor Score (eigenvalue) for the "Marriage" concept. It would be easy, therefore, to compute a correlation between one person's factors scores for all factors/dimensions and another person's factor scores.

For readers who know something about factor analysis . . . Since eHarmony uses Principal Components factor analysis, they would more than likely use Kaiser's Normal Varimax Rotation to identify significant factors (those with eigenvalues greater than 1.0).

Note: For anyone who wants to complete the eHarmony questionnaire, you should be able to identify the 14 or so questions for each of the "29 Dimensions of Compatibility." Each factor's 14 (or so) questions may be spread randomly throughout the questionnaire, or they may follow a simple pattern. If a "Marriage" factor exists, and one of the "Marriage" questions is #1, then the other 13 marriage questions would be in positions 30, 59, 88, 177, 146, 175, 204, 233, 262, 297, 320, 349, and 378. Now, I'm not suggesting that you do this, but if you want to be consistent with your answers, make sure you answer each factor's questions in the same way—that is, answer the negatively leaned questions with a negative rating, and the positively leaned questions with a positive rating. This is cheating, but that is the way to "fool the computer" if you have a desire to do so.

So What?
From the information I read, it appears that eHarmony has probably followed the correct steps in producing a questionnaire and uses simple statistical methods to analyze the data, but this doesn't mean that the methodology is valid and reliable. However, even if the methodology is valid and reliable, it doesn't necessarily follow that the "matching" aspect of the process will be successful. My guess is that much of the success with eHarmony is based on a self-fulfilling prophecy developed by those who use the website. In other words, the people are determined to find someone, invest their time and money into the website, and are convinced the method will work.

The process of answering about 430 questions to find a soulmate or partner may overlook (or be incapable of identifying) some major differences. The 430 questions may indicate a "match" according to eHarmony's methodology, but the match does not necessarily mean that the couple will have a successful relationship, and, to eHarmony's credit, they do mention that there are no guarantees. For example, the questionnaire may indicate a match with two people, but when the two people meet, they both might sing: U-G-L-Y, you ain't got no alibi. You ugly, uh-huh, you ugly. (Sorry, I have wanted to use that "cheer" from the 2007 remake of the movie, "The Longest Yard" for a long time. However, regardless of my cynicism, compatibility on answering questions does not necessarily equate to success in a relationship.)

Now on to the most important point of the whole Internet dating process . . .

Regardless of whether the methodology of any Internet dating website is valid and reliable, the aspect of safety overshadows any concern for the correctness of the methodology.

Once again, to eHarmony's credit, the company includes a section on its website called, "eHarmony Advice," and I think it's important to read everything there if you plan to use the site. For example, there is a section called 5 Dating Rules you Should Never Break.

In addition, you should carefully read eHarmony's Terms of Service section. Some of the things in that area include:

1. Eligibility
a. Minimum Age. You must be at least 13 years old to use the Site (or the age of majority in your jurisdiction, if it is older), and at least 18 years old to register for the Services. By using the Singles Service, you represent and warrant that you are at least 18 years old. Other Services may have other age requirements for all or portion of such Services, and such other age requirements are stated on such Services or portions thereof.

b. Marital Status. By requesting to use, registering to use, or using the Singles Service, you represent and warrant that you are not married. If you are separated, but not yet legally divorced, you may not request to use, register to use, or use the Singles Service.

c. Criminal History. By requesting to use, registering to use, and/or using the Singles Service, you represent and warrant that you have never been convicted of a felony and are not required to register as a sex offender with any government entity. EHARMONY DOES NOT CURRENTLY CONDUCT CRIMINAL BACKGROUND SCREENINGS ON ITS MEMBERS. However, eHarmony reserves the right to conduct a criminal background check, at any time and using available public records, to confirm your compliance with this subsection.

In addition, Part D of the section titled, "Use of Site and Service," states,

Risk Assumption and Precautions. You assume all risk when using the Services, including but not limited to all of the risks associated with any online or offline interactions with others, including dating. You agree to take all necessary precautions when meeting individuals through the Singles Service. In addition, you agree to review and follow the recommendations set forth in eHarmony’s Safety Tips, which will be provided to you prior to entering the “Open Communication” phase with your matches in the Singles Service and is available at the bottom of all pages of the Singles Service. You understand that eHarmony makes no guarantees, either express or implied, regarding your ultimate compatibility with individuals you meet through the Singles Service or as to the conduct of such individuals. You further understand that eHarmony makes no guarantees as to number or frequency of matches through the Singles Service.

While the Terms of Service is several pages long. I strongly urge you to read the entire document if you intend to use eHarmony.

While I give credit to eHarmony and other dating websites for including precautions about using the service, I don't think the cautions are strong enough. Here is why . . .

It would be easy for any "evil" person to take advantage of any of the dating websites. For example, with the eHarmony site, a person with knowledge of questionnaire design and how to cheat on answers could easily find matches with almost anyone—just answer the questions "correctly." I know that most of the dating websites say that they have never had a problem, but that doesn't mean something won't happen in the future.

If you read some of the "Terms of Service" from eHarmony I included above, you should remember reading this (I'm repeating it because I want to make sure every reader sees it):

Criminal History. By requesting to use, registering to use, and/or using the Singles Service, you represent and warrant that you have never been convicted of a felony and are not required to register as a sex offender with any government entity. EHARMONY DOES NOT CURRENTLY CONDUCT CRIMINAL BACKGROUND SCREENINGS ON ITS MEMBERS. However, eHarmony reserves the right to conduct a criminal background check, at any time and using available public records, to confirm your compliance with this subsection.

Oh, please. AS IF a convicted felon/sex offender is going to answer that question honestly. And that's the problem . . . the people who use the dating websites in hopes of finding "Mr./Ms Right" may actually find "Mr./Ms Convicted Felon." So, if you use the dating websites, please be very cautious. There is no methodology on this planet that can guarantee that the person you are matched with is a nice/kind human being.

Final Opinion
Based on the limited information about eHarmony's methodology contained in the patent summary, I don't see anything wrong with the procedures. The statistics used are very basic and there is no indication that a new statistical procedure or algorithm (formula) was developed. Correlation, linear regression, and factor analysis have been used for many decades, and this makes me wonder about how eHarmony received a patent the company received.

In order for me to give a 100% approval score or some form of overall "pass" grade, I would need to have access to a lot more information. However, for the time being, the methodology seems OK. What you have here is a simple methodology with an excellent marketing plan. The methodology isn't unique, but the people who designed the marketing plan know what they're doing—they have taken a simple procedure and made it into a "big deal."

So, while I say that the methodology is OK, I still want to emphasize the necessity to be very cautious with the service—not just eHarmony, but with every dating service on the Internet.

Correlation is a number from –1.00 to +1.00. A positive correlation indicates that the elements being tested are similar. A correlation of +1.00 if called a "perfect positive correlation," which means that the elements tested are essentially identical. A correlation of -1.00 if called a "perfect negative correlation," which means that the elements tested are essentially opposite. A zero correlation means that there is no relationship at all between the elements tested.

As Joe Dominick and I state in our book, Mass Media Research: An Introduction, 9th Edition (page 321), A correlation coefficient is a pure number; it s not expressed in feet, inches, or pounds, nor is it a proportion or percentage. The Pearson r is independent of the size and units of measurement of the original data.

Just ONE More Thing
OK. That's it. Enough with all the frivolity. It's time to get serious.

After reading all the information about Internet dating, I decided that "enough is enough" and I'm tired of seeing all these companies make money just by helping people finds dates. So I created my own. It's time for me to get my share of the fun and money.

So . . . to see the latest dating site on the Internet, just Click Here.

(Want to comment on this question? Click on the POSTREPLY button under the question.)
Roger Wimmer is owner of Wimmer Research and senior author of Mass Media Research: An Introduction, 10th Edition.

User avatar
Posts: 197
Joined: Mon Sep 28, 2009 12:40 pm

Re: eHarmony Method – How does it work?

Post by rogerwimmer » Wed Mar 31, 2010 4:05 pm

Doc: Thanks for the information. Great answer! Your new dating test is really funny. You are one sick puppy. - Anonymous

Anon: You're welcome for the information. Sick puppy? Thanks. I will alert my wife.
Roger Wimmer is owner of Wimmer Research and senior author of Mass Media Research: An Introduction, 10th Edition.

Post Reply