Not 29 dimensions, it’s really 35.

A rant on why 29 is a magic number to eHarmony, like 47 is to Star Trek….

The eHarmony test measures most of the 29 dimensions using a mathematical technique called “statistical sampling.” For example, questions measuring Dominance appear ten times during the 436-item test. Using these ten replies, the system gives a Dominance score and assesses them to say whether the Dominance score is valid and reliable. The values are those bar graphs on TV. OK, the graphics are awesome.

Psychometric tests must be valid and reliable to be useful. The way to do that is multiple questions that gather several samples. Two of the 29 dimensions don’t do that.

Family status is not a quantifiable quality. A bar graph of family status make no sense. The site defines the metric as whether “do you have children from a previous relationship or marriage, do they live with you full time/part time/not at all, are they under the age of 18, etc.” Whoa,

First, “do you have children from a previous relationship or marriage” and “are they under the age of 18″ are not even anywhere in the test.
“How many children do you have who are 18 years old or younger and living full time in your home?” is a Match Setting that any member can change anytime.
How on earth can we assign a number to this? Do we base a dimension on the answer to just one question? How reliable is that?

Education is another Match Setting that any member can change anytime. It’s another metric based on only one question. How can eH say they match members of equal education background when anyone can be a PhD anytime with three mouse clicks? That‘s false advertising!

If two Match Settings (that any member can change anytime to broaden or narrow his or her search results) can be counted as dimensions, then why stop there? Let’s call

30. Distance
31. Smoking Habits
32. Drinking Habits
33. Age
34. Religion and
35. Ethnicity

dimensions, too. (Hey, physicists will even say that distance is already a dimension.)

If eHarmony makes a commercial on Age like they did with Humour, I bet they get more sign ups. (But wait, see I think the difference in age between us is too great..)