One thing I’ve never really seen mentioned in discussion of the planning fallacy is that there is something of a self-defeating prophecy at play.
Let’s say I have a report to write, and I need to fit it in my schedule. Now, according to my plans, things should go fine if I take an hour to write it. Great! So, knowing this, I work hard at first, then become bored and dick around for a while, then realise that my self-imposed deadline is approaching, and—whoosh, I miss it by 30 minutes.
Now, say I go back in time and redo the report, but now I assume it’ll take me an hour and a half. Again, I work properly at first, then dick around, and—whoa, only half an hour left! Quick, let’s finish thi—whoosh.
The point I’m trying to make here is that sometimes the actual length of a task depends directly on your estimate of that task’s length, in which case avoiding the planning fallacy simply by giving yourself a larger margin won’t work.
But I suppose the standard argument against this is that to properly counteract this kind of planning fallacy, one mustn’t just take out a longer span of time, but find what it is that makes one miss the deadline and correct it.
I’m not 100% sure I understand the self-defeating prophecy point, but there have been a few studies that argue that your planned completion time actually affects reality like you say.
Some psychologists also make a distinction between “time spent working on task” (which people seem to be good at sorta knowing) and “time when people are actually finished with a task” (which they often get wrong because they forget about unknown unknowns).
I agree that counteracting poor planning also requires you to look at ways you failed:
The techniques I cover, Murphyjitsu, RCF, and Back-planning all tackle slightly different things. Murphyjitsu helps you identify potential failure modes so you can patch them. RCF helps you rescale estimates, but can also identify past choke points. Back-planning, I will admit, is mainly for estimates.
One thing I’ve never really seen mentioned in discussion of the planning fallacy is that there is something of a self-defeating prophecy at play.
Let’s say I have a report to write, and I need to fit it in my schedule. Now, according to my plans, things should go fine if I take an hour to write it. Great! So, knowing this, I work hard at first, then become bored and dick around for a while, then realise that my self-imposed deadline is approaching, and—whoosh, I miss it by 30 minutes.
Now, say I go back in time and redo the report, but now I assume it’ll take me an hour and a half. Again, I work properly at first, then dick around, and—whoa, only half an hour left! Quick, let’s finish thi—whoosh.
The point I’m trying to make here is that sometimes the actual length of a task depends directly on your estimate of that task’s length, in which case avoiding the planning fallacy simply by giving yourself a larger margin won’t work.
But I suppose the standard argument against this is that to properly counteract this kind of planning fallacy, one mustn’t just take out a longer span of time, but find what it is that makes one miss the deadline and correct it.
Hey jollybard,
I’m not 100% sure I understand the self-defeating prophecy point, but there have been a few studies that argue that your planned completion time actually affects reality like you say.
Some psychologists also make a distinction between “time spent working on task” (which people seem to be good at sorta knowing) and “time when people are actually finished with a task” (which they often get wrong because they forget about unknown unknowns).
I agree that counteracting poor planning also requires you to look at ways you failed:
The techniques I cover, Murphyjitsu, RCF, and Back-planning all tackle slightly different things. Murphyjitsu helps you identify potential failure modes so you can patch them. RCF helps you rescale estimates, but can also identify past choke points. Back-planning, I will admit, is mainly for estimates.