The hammer rang once. A spark jumped off the anvil and did not go out. It waited. They followed.

Coach Brennan had been running the school basketball team for ten years, and in all that time Tara had never heard anybody say a bad word about him that they meant. He drove the minibus himself. He bought oranges for half-time out of his own pocket. When Tara's brother Arjun broke his wrist in his first season, Coach Brennan had visited the house with a get-well card signed by the whole team and a book about the history of the jump shot, which Arjun had read four times.

So when the parents' meeting was held at the Whetstone on a wet Thursday evening, and Coach Brennan stood up at the front with a sheet of paper, everybody listened.

Tara was at the back table, as usual, with her homework. She had come to pick up Arjun. She had not meant to listen. She listened anyway.

"I want to put something to you all," said Coach Brennan. "I've been keeping notes all season. Twelve games. And I've noticed something, and I want to make it the team rule from now on."

He held up the paper.

"After a bad game, I've been tough on them. I mean properly tough. Raised voice, laps, the lot. And every single time, the next game, they've played better. Every time. And after a good game, I've praised them. Told them how proud I was. And every single time, the next game, they've played worse." He put the paper down. "I don't enjoy shouting. You all know me. But the numbers don't lie. Praise makes them comfortable. Pressure makes them sharp. So I'm proposing: from now on, tough after a bad game, and no gushing after a good one. I'd like the parents' support for that."

There was a murmur round the room. It was not a disagreeing murmur. It was the murmur of people hearing something that matched what they already suspected about teenagers.

"It's true," said one father. "My lad gets lazy the minute anyone tells him he's good."

"Mine too," said someone else.

Tara remembered the drive home after the forty-nine. It had been the worst game of the season, a home game, in front of the whole school. Arjun had sat in the passenger seat with his kit bag on his knees and said nothing for six streets. Then he had said, to the window, "He made us run until Theo was sick. And he kept saying we didn't care. We did care. That was the whole problem. We cared and we were still rubbish."

"Did it help?" Tara had asked. "The running?"

Arjun had thought about it for a long time. "We won the next one," he had said at last. "So I suppose it did." But he had not sounded like he believed it. He had sounded like someone repeating a sum he could not check.

Tara looked at Arjun, who was sitting on the edge of a chair by the door in his tracksuit. He was looking at the floor. He hated the shouting. He had told her so in the car, more than once. But he also could not argue with the pattern. Nobody could. It was right there on the paper.

"Can we have a show of hands?" said the woman chairing the meeting. "In support of the coach's approach?"

Hands began to go up. Quite a lot of hands.

"Can I ask something first?"

It was Kiran, the team's point guard. He was sitting near Arjun, tall and serious, the kind of player who looked at the whole court before he passed. Tara knew him a little. He was in her maths set. He did not say much there either, but when he did, the teacher stopped writing on the board.

"Of course," said Coach Brennan, a little surprised.

"I'm not saying you're wrong," said Kiran. "I want that to be really clear, Coach. I'm saying I don't think we can tell yet." He hesitated. "After every bad game, you yelled, and the next game was better. But what else changed between those games? I mean, what would have happened if you hadn't yelled?"

"They'd have played the same," said the father who had spoken before. "Or worse."

"Maybe," said Kiran. "But we don't know that. We've never seen it. Every time we played badly, he yelled. So we've got no games to compare with. It happened after. That's not the same as because."

Several of the raised hands came down a little, not all the way, the way hands do when their owners are not sure any more.

"Moving together isn't the same as causing," said Kiran, more quietly. "That's all I'm saying."

Coach Brennan looked at him for a long moment. He did not look angry. He looked like a man who has been asked a fair question by someone he respects and is trying to decide whether he is about to lose an argument.

"Fair enough," he said at last. "So what would convince you?"

Kiran did not have an answer. He looked round the room. His eyes landed on the back table, where Sofia was sitting with her notebook.

Sofia was the team's statistician, which was a job she had invented for herself in Year Nine. She sat at every game with a notebook and wrote down every score, every foul, every substitution. Nobody had asked her to. Coach Brennan had stopped questioning it after she had once told him, to the minute, how long his best shooter had been on the bench in a game they lost by two.

She stood up and came to the front.

"Can I write all twelve down first?" she said. "Before anybody votes. On the board."

There was a whiteboard by the Whetstone's counter that usually listed the soups. Sofia wiped it, very carefully, and wrote out the season, one game after another:

52, 71, 58, 66, 49, 63, 74, 57, 61, 68, 55, 62.

"That's our points in each game," she said. "In order."

People looked at it. It looked like a list of numbers. It did not look like it was going to say anything.

"The average is about sixty-one," said Sofia, and drew a line across the board at that height. "Most of our games are near it. A few are way below and a few are way above. Look at the whole season, not one game."

She circled the three lowest scores: 49, 52 and 55.

"These are our three worst games," she said. "After each of them, Coach was tough with us. And look what came next." She drew arrows. "After forty-nine, sixty-three. After fifty-two, seventy-one. After fifty-five, sixty-two. All higher. Every one."

"Exactly," said Coach Brennan.

"Now our three best," said Sofia, and circled 74, 71 and 68. "After each of these, Coach praised us. What came next? After seventy-four, fifty-seven. After seventy-one, fifty-eight. After sixty-eight, fifty-five. All lower. Every one."

"Exactly," said Coach Brennan again, but more slowly.

Sofia put the pen down.

"Here's the thing that bothers me," she said. "Every team has a spread. Some days you're on, some days you're not, and a lot of that is stuff nobody controls. Whether the other team's best player turned up. Whether your shooter slept. Whether the ball bounces off the rim or in. When we have a really, really bad day, a lot of things went wrong at once, and some of those were luck. And luck doesn't usually stay that bad two games running. So the next game is usually more ordinary. Closer to the line."

She tapped the line at sixty-one.

"And a really, really good day," she said, "is the same, the other way round. Some of it was us. Some of it was things going right that won't go right again next time. So the next game is usually more ordinary, too. Lower."

Theo, the team's tallest player, put his hand up. He was the one who had been sick after the laps.

"I just want to say something for Coach," said Theo. "Before the forty-nine I was coasting. I know I was. I was turning up late to practice. After that night, I stopped. I got to every practice early for the rest of the season. That's real. That's not a number on a board. Something changed in me."

"I believe you," said Sofia, and she sounded like she meant it. "That might be completely true. It just isn't something these twelve numbers can show. They'd look like this whether it was true or not."

Theo frowned, and sat back down, and did not look convinced. But he did not look angry either.

"So you're saying the yelling did nothing," said the father.

"No," said Sofia. "I'm saying that if Coach had done nothing at all, these numbers might look exactly the same. I'm saying I can't tell from these. A very bad day is usually followed by a more ordinary one. Whatever you do in between."

The room was quiet. Somebody's phone buzzed and they turned it off without looking.

Danya had come with Tara, as he often did, and had been pretending to read a comic. He put it down.

"So how do we know?" said Danya. Everyone turned to look at him. He was twelve and small for his age, and he was not even on the team. "If we can't tell from those games, how would we ever tell?"

"Toss a coin," said a voice from the doorway.

It was Yara, a senior who ran the science fair and had a reputation for being impossible to argue round, mostly because she was usually right and always cheerful about it. She had come to collect her younger sister from the meeting and had clearly been standing in the doorway for some time.

"Sorry," said Yara, not sounding sorry. "But it's the only fair test. After every bad game for the rest of the season, Coach tosses a coin. Heads, he does the tough talk. Tails, he does something else: talks it through calmly, or just says 'next game'. Then at the end, you compare. Do the heads games bounce back more than the tails games?"

"That's ridiculous," said someone. "You can't run a team by coin toss."

"You can for one decision," said Yara. "And it's the only way to know. If Coach chooses when to be tough, he's already biased it. He might be tough on the days he can tell they're about to come back anyway. Let chance pick, then compare. A fair test, or it's just a story."

Coach Brennan rubbed the back of his neck.

"It feels wrong," he said. "Not shouting at them when they've played badly. Like I'd be letting them down."

"It might be," said Yara. "That's what the test is for. If the tough talk really works, the heads games will show it, and you'll have proof instead of a feeling. And if it doesn't, you'll have stopped shouting at fifteen-year-olds for nothing." She shrugged. "Either way you win."

Kiran looked at Theo, and Theo looked at Arjun, and something passed between the three of them that the parents did not see.

"We'd do it," said Kiran. "The team, I mean. If it's a coin, it's not you deciding we don't care. It's just the coin. We'd still play hard either way. That's sort of the point."

"And we'd know," said Arjun. It was the first thing he had said all evening. His voice cracked a little on it, and he went red, but he kept going. "At the end of the season we'd actually know. Instead of just guessing every time."

Coach Brennan looked at his three players for a long time. Then he looked down at his sheet of paper, the one with his twelve games on it, as if he were seeing it for the first time.

Nobody voted. The chairwoman looked at her list and then at the clock, and the meeting began to come apart into small conversations, the way meetings do when the thing that was supposed to happen has stopped happening.

Coach Brennan did not sit down. He stood at the front by the whiteboard with its circled numbers, and he looked tired. He looked, Tara thought, like a man who had given ten years of Saturdays to something and was afraid he had been doing part of it wrong.

He was not a villain. That was the hard part. He cared about every one of them. He had driven Arjun to hospital. He had found something that seemed to work, and he had been brave enough to write it down and bring it to a room full of parents. Kiran was right that they could not tell yet. Sofia was right about the spread. Yara was right about the coin. And the parents were right that teenagers sometimes coast when they are praised. Everybody in the room was partly right.

Coach Brennan's eyes went round the café and stopped at the back table.

"Tara," he said. "You're Arjun's sister. You've sat through more of our games than most of these parents. You haven't said anything all evening. You usually don't." He gave a small, tired smile. "What do you think?"

Arjun looked up from the floor for the first time.

The room went still. The rain ticked on the window. Somewhere behind the counter, the coffee machine sighed.

Tara had listened to all of them. The father whose lad got lazy. Kiran with his after and his because. Sofia with her line at sixty-one. Yara with her coin. Arjun, in the car, saying he hated it. Coach Brennan, at the front, afraid.

Tara opened her mouth.

 

 

(Write the sentence Tara says.)

 

The spark dimmed to a warm dot and settled back on the anvil. The Green was just the Green again.

Back on the Green

A few weeks later Danya got the worst spelling score of his life, eleven out of twenty, and his mother said, "Right, no screens until it's better."

The next week Danya got sixteen.

"See," said his mother. "It worked."

Danya opened his mouth to agree. Then he stopped, and looked at Tara, who was on the sofa with a book, and Tara raised one eyebrow without looking up.

"Maybe," said Danya slowly. "Or maybe eleven was just a really bad day."

Afterword. The idea in this case has a name: regression to the mean. When a result is unusually far from average, part of the reason is luck, and luck does not usually repeat; so the next result tends to be more ordinary, whatever you do in between. The psychologist Daniel Kahneman told a famous version: flight instructors who were sure that shouting after a bad landing worked and praising a good one backfired, when the pattern came from the landings alone. You can play with luck and the long run in ChanceForge, and with fair tests in InquiryForge.