(NBC) - Your wedding day is usually one of the happiest days of your life, but how can you be sure the relationship will stand the test of time?
A group of Swiss statisticians has come up with a very unromantic formula to determine whether your marriage will last.
According to a study of over 1000 married or co-habitating couples, the ideal wife would be five years younger, come from the same cultural background and be 27 percent smarter than her husband.
By following these guidelines, the researchers say you could increase you're chances of having a happy marriage by up to 20-percent.
The Swiss formula seems to add up for Celia and Robert Sullivan have been together for years.
Celia is six years younger and Robert says she's no dummy.
"She is a very smart person, smart enough to marry me and stay with me all this time," says Robert.
"I think it is interesting from the point of view of a mathematical mode, but in some senses Yeah I think it is baloney," says Dr. Sara Corse from the Council for Relationships.
She adds that men may be attracted to someone who is younger or smarter, or comes from a similar background, but says those factors aren't a "formula" for success.
She says what you should look for is love, chemistry, friendship, and similar values.
"There's no magic formula. There's no one secret. Relationships are hard, they are extremely rewarding but you also have to work at them," says Dr. Corse.