These were the findings he’d reached so far:

Higher income was associated with higher happiness, but in diminishing returns. For example, someone who made $50,000 reported being happier than the man with a salary of $25,000. But the incremental gain in happiness that came from getting a raise from $50K to $100K was much less.

In spite of material improvements, happiness is flat over time-relative income might be more important than absolute income gains.

Well-being was greatest among women, married people, the highly educated, and those whose parents didn’t divorce.

Women’s happiness was declining over time, possibly because they’d reached greater equality with men in the labor market.

Blacks in the U.S. were much less happy than whites, but their life satisfaction was on the upswing.

Calculations indicated that “reparation” for being unemployed would take $60,000 per year. “Reparation” for being black would take $30,000 per year. “Reparation” for being widowed or separated would take $100,000 per year.

There was a game Lewis used to play with himself, after the kids were born, when he was feeling so ridiculously lucky that surely tragedy was bound to strike. He’d lie in bed and force himself to choose what he was first willing to lose: his marriage, his job, a child. He would wonder how much a man could take before he reduced himself to nothing.

He closed the data window and stared at the screen saver on his computer. It was a picture taken when the kids were eight and ten, at a petting zoo in Connecticut. Joey had hoisted his brother up, piggyback, and they were grinning, with a striated pink sunset in the background. Moments later, a deer (deer on steroids, Lacy had said) had knocked Joey’s feet out from beneath him and both boys had fallen and dissolved into tears…but that was not the way Lewis liked to recall it.

Happiness wasn’t just what you reported; it was also how you chose to remember.

There was one other finding he’d catalogued: happiness was U-shaped. People were happiest when they were very young and very old. The trough came, roughly, when you hit your forties.

Or in other words, Lewis thought with relief, this is as bad as it gets.

Although Josie got A’s in math and liked the subject, it was the one grade she had to fight for. Numbers did not come easily to her, although she could reason with logic and write an essay without breaking a sweat. In this, she supposed, she was like her mother.

Or possibly her father.

Mr. McCabe, their math teacher, was walking through the rows of desks, tossing a tennis ball against the ceiling and singing a bastardized Don McLean song:

“Bye, bye, what’s the value of pi

Gotta fidget with the digits

Till this class has gone by…

Them ninth graders were workin’ hard with a sigh

Sayin’, Mr. McCabe, come on, why?

Oh Mr. McCabe, come on, why-y-y…”

Josie erased a coordinate from the graph paper in front of her. “We’re not even using pi,” one kid said.

The teacher whirled around and tossed the tennis ball so that it bounced on the boy’s desk. “Andrew, I’m so glad to see you woke up in time to notice that.”

“Does this count as a pop quiz?”

“No. Maybe I should go on TV,” Mr. McCabe mused. “Is there a Math Idol?”

“God, I hope not,” Matt muttered from the desk behind Josie. He poked her shoulder and she pushed her paper to the upper left corner of her desk, because she knew he could see the homework answers better there.

This week they were working on graphing. In addition to a bazillion assignments that made you take data and force it into bar graphs and charts, each student had had to create and present a graph of something near and dear to them. Mr. McCabe left ten minutes at the end of each class period for the presentation. Yesterday, Matt had shown off a graph of relative age of hockey players in the NHL. Josie, who was presenting hers tomorrow, had polled her friends to see if there was a ratio between the number of hours you spent doing your homework and your grade point average.

Today was Peter Houghton’s turn. She had seen him carrying his graph into school, a rolled-up piece of poster board. “Well, look at that,” Mr. McCabe said. “Turns out we are talking about pie. The other one, that is.”

Peter’s graph was a pie chart. It had been clearly shaded with colors, and computer labels identified each section. The title at the top of the chart said POPULARITY.

“Whenever you’re ready, Peter,” Mr. McCabe said.

Peter looked a little bit like he was going to pass out, but then, Peter always looked like that. Since Josie had started working at the copy shop, they’d been talking again, but-by unwritten rule-only outside of school. Inside was different: a fishbowl where anything you said and did was being watched by everyone else.

When they were kids, Peter had never seemed to notice when he was drawing attention just by being himself. Like when he’d decide to speak Martian during recess, for example. Josie supposed that the flip side of this, the optimistic angle, was that Peter never tried to be like anyone else. She couldn’t lay claim to that herself.

Peter cleared his throat. “My graph is about status in this school. My statistical sample came from the twenty-four students in this class. You can see here”-he pointed at one wedge of the pie-“that a little less than a third of the class are popular.”

Shaded violet-the color of popularity-were seven wedges, each sporting a different classmate’s name. There was Matt, and Drew. A few girls who hung out at lunchtime with Josie. But the class clown was also lumped in that group, Josie noticed, and the new kid who’d transferred from Washington, D.C.

“Over here are the geeks,” Peter said, and Josie could see the names of the class brain and the girl who played tuba in the marching band. “The largest group is what I call normal. And roughly five percent are outcasts.”

Everyone had grown quiet. This was one of those moments, Josie realized, when the guidance counselors would get called in to give everyone a booster shot of tolerance for differences. She could see Mr. McCabe’s brow furrow like origami as he tried to figure out how to turn Peter’s presentation into an After School Special moment; she saw Drew and Matt grinning at each other; and most of all, she noticed Peter, who was blissfully unaware that all hell was about to break loose.

Mr. McCabe cleared his throat. “You know, Peter, maybe you and I should-”

Matt’s hand shot up. “Mr. McCabe, I have a question.”

“Matt-”

“No, seriously. I can’t read that skinny piece of the pie chart. The orange one.”

“Oh,” Peter said. “That’s a bridge. You know. A person who can fit into more than one category, or who hangs out with different kinds of people. Like Josie.”

He turned to her, beaming, and Josie felt everyone’s eyes on her-a hail of arrows. She curled over her desk like a midnight rose, letting her hair fall over her face. To be honest, she was used to being stared at-walk anywhere with Courtney and it was bound to happen-but there was a difference between people looking at you because they wanted to be like you, and people looking at you because your misfortune brought them one rung higher.

At the very least, kids would remember that once, Josie had been an outcast who used to hang out with Peter. Or they’d assume that Peter had some weird crush on her, which was just sick, and she’d never hear the end of it. A murmur ran through the classroom like an electric shock. Freak, someone whispered, and Josie prayed prayed prayed that they were not talking about her.

Because there was a God, the bell rang.

“So, Josie,” Drew said. “Are you the Tobin or the Golden Gate?”