“My husband had been trying to sell me on his method for years before I finally relented. An efficiency consultant who had once worked in the car industry in Japan, he wanted to “Toyota Way” our lives. I wanted him to keep his spreadsheets to himself.

But a house, a baby and some career changes later, as I was folding tiny T-shirts while doing an interview and rocking the baby’s chair with my foot, I gave in. I was overwhelmed. Maybe a spreadsheet could help after all.

The method, as my husband would be shouting right now, is of course more than just a spreadsheet. It’s based on the Japanese notion of “kaizen,” or continuous improvement, made famous in 2001 when Toyota singled it out as one of the pillars of the company’s success. You pick a goal, figure out the main components behind it, collect data on those components and work out what you can do to move closer to the goal.

In the case of Toyota, the goal was higher quality and increased profits. When we translated the idea to our home life, the goal was a little simpler but also a lot more complicated — happiness. We weren’t sure what drove it, so we decided to collect data on everything: how many hours we were sleeping a night, how long we spent on housework or child care, the amount of alone time, social time, commuting time, you name it. We assigned a score from one to 10 to each day, and then gave a primary reason for each score: not enough sleep, work sucked and, sometimes, ‘relationship bad feeling.’”