Associated Press
"For Better: The Science of a Good Marriage" by Tara Parker-Pope

Countless self-help books have been written about marriage. It's the rare work, however, that has the rigor and factual grounding of "For Better: The Science of a Good Marriage."

Written with a sharp eye by New York Times health reporter Tara Parker-Pope, the book examines research studies on marriage and distills their findings into lessons for couples. Some are more convincing than others. Researchers have found, for example, a parallel between housework and sex: The happier wives are about the division of chores, the happier husbands are with their sex lives.

"Men said that if they did housework, their wives were happier with them. It's a sign that he is appreciating her, thinking about her and caring about her. Those tend to be things that lead to her warming up to him when it comes to sex," says Neil Chethik, author of "VoiceMale: What Husbands Really Think About Their Marriages, Their Wives, Sex, Housework, and Commitment," who surveyed 300 American husbands.

It's more of a leap, however, for Parker-Pope to suggest that since scientists found strong marriages to have at least a 5-to-1 ratio of good-to-bad interactions, it behooves the reader to do five positive things to cancel out an instance of mistreating a spouse.

The book is most useful in the neat interactive and introspective exercises that demonstrate a research finding or help readers diagnose the state of their marriage. Parker-Pope artfully expounds on technical studies with layman-friendly examples.

For instance, researchers have found that the difference between a productive fight and a harmful fight lies in whether it begins with a complaint or criticism: "I really need more help juggling the kids' schedules on the weekend. I'd like some time for myself, too," versus, "All you think about is yourself. Why would it never occur to you that I might need some help with the kids or there might be something I want to do today?"

Many of the scientifically proven predictors of divorce can act as a red flag for couples to intervene before things escalate. If you find yourself telling your how-we-met story cynically, Parker-Pope writes, or frequently rolling your eyes at your spouse, it's time to take a step back and identify any hidden resentments or frustrations.

"For Better" is a trove of interesting tidbits. For women out there who wonder why men don't initiate difficult discussions, Parker-Pope has your answer: Conflict is physiologically draining for men — their hearts beat faster and blood pressure stays high longer than women in similar situations.

Oh, and that statistic about 50 percent of marriages ending in divorce? That was the peak in divorce rates, for the generation of couples who married in the 1970s, and Parker-Pope argues it "isn't particularly relevant to people who have gotten married more recently or are planning to marry in the future." The misleading statistic, she writes, "leaves us assuming marriage is more fragile than it really is, and it makes us ambivalent and more vulnerable to giving up when problems occur in our own relationships."

Armed with studies showing the health and financial perks to being married, and sharing proven ways to achieve a happy union, Parker-Pope succeeds in making a convincing argument for investing in and improving our marriages.