It Will Take Longer

Hi friend,

In the early 1970s, a young psychologist named Daniel Kahneman persuaded Israel’s Ministry of Education to let him write a high school textbook on judgment and decision-making.

He gathered a team at the Hebrew University: experienced teachers, a few of his own students, and Seymour Fox, dean of the School of Education and an expert in building curricula. After a year they had an outline, two chapters drafted, and some sample lessons tried out in real classrooms. The work was going well, and everyone in the room felt it.

At one meeting Kahneman asked each of them to write down, privately on a slip of paper, how long it would take to hand the finished textbook to the Ministry. He collected the slips. The answers sat in a narrow band, from eighteen months to two and a half years.

Then he turned to Fox, who had written his own slip with the rest of them, and asked a different question. Think of other teams who tried to build a new curriculum from scratch. When they were at the stage we’re at now, how long did it take them to finish?

Fox was quiet for a while. Then he said that, now he thought about it, not all of them had finished. About 40 percent never did. Of the ones that finished, he could not think of any that took less than seven years, or any that took more than ten.

Kahneman asked one more question: how did this team compare with those others? Fox said they were below average, though not by much.

What makes the story worth telling is what happened next.

Nobody quit. The team had just learned, from its own expert, that it was likely to take three or four times longer than planned and stood a real chance of never finishing at all, and it carried on as before. Kahneman later wrote that the sensible choice would have been to break up. Instead they abandoned good sense and kept the project.

The textbook was finished eight years later. By then Kahneman had left the team and the country, the Ministry had lost interest, and the book was never used.

Notice the strangest part. Fox had both numbers in his head the whole time. Asked about this team, he wrote two years. Asked about teams like this one, he knew the answer was seven to ten. The information was never missing. He was simply looking at the project from the wrong side.

Kahneman called the two sides the inside view and the outside view. The inside view looks at your plan, your team, your progress so far, and builds a forecast from the details. The outside view ignores the details and asks how long things of this kind usually take for people like you. With Amos Tversky, he gave the error a name that stuck: the planning fallacy.

In 1994, three psychologists in Canada, Roger Buehler, Dale Griffin and Michael Ross, tested it on students writing their honours theses.

They asked each student when he expected to finish. The average answer was 33.9 days. The average student took 55.5. Only about three in ten finished by the date they had chosen.

The researchers also asked the students for a worst case, the date they would finish if everything went as badly as it possibly could. The average worst case was 48.6 days, and the average student still came in a week behind it.

Two more findings from that work are the ones to keep. People’s estimates for other people’s projects were far less optimistic than their estimates for their own. And they would readily admit that their past projects had run late, while insisting that this one was different.

I would like to say I am above this. Nobody is, and that is the point of the thesis study: knowing about the error does not protect you from it.

The reason is in how a plan gets built. When you picture a project from the inside, you picture the steps you can see, in order, going roughly the way steps go. What you cannot picture is the week you get ill, the client who goes silent, the part you have to redo, the second job that eats your evenings. Each of those is unlikely on its own, so none of them makes it into the plan. But there are hundreds of them, and the odds that at least one arrives are close to certain.

So the outside view is not pessimism. It is the only estimate that already contains the things you could not have seen coming.

Here is how to use it.

Find the reference class. Before you plan anything, ask how long similar projects took for people at your level. The launch, the first ten clients, the book, the degree. Ask people who have done it, and ask the way Kahneman asked Fox: not how long should it take, but how long did it take.

Check your own record. Look at the last three things you set out to do and compare the date you gave yourself with the date you finished. That ratio is a better forecast than any plan you will write today.

Let someone else estimate it. The thesis students were far more accurate about other people’s work than their own. Describe your project to someone who has no stake in it and ask for their guess.

Start from the outside number and adjust from there. Move it only for reasons someone else could check. We really believe in it is not one of them.

Then ask the question Kahneman’s team skipped. If this takes twice as long as I think, do I still want to start it? If the answer is yes, go, and plan your money, energy and patience for the longer road. If the answer is no, you have just saved yourself the eight years.

The team did not fail because it worked slowly. It failed because it planned for two years, lived through eight, and never decided anything differently in between.

What are you working on right now, and how long did it take the people who did it before you?

Until next time
Lorenc - Founder of Success Skill