What is the akrasia horizon?
It means you can't make your goal easier any earlier than 7 days from today.
In practice, that means that changing the goal parameters, quitting/archiving the goal, and lowering the amount of money at stake are all changes that don't happen immediately. Beeminder is about committing to goals, so we intentionally make it hard to get out of your commitment. If you could just change the terms and make it easier any time you wanted, you might never get anything done — completely defeating the purpose of creating the goal!
Why a week? Akrasia (see also: dynamic inconsistency, hyperbolic discounting) means over-weighting immediate consequences (such as the pleasure of an evening of gaming) instead of properly considering the long-term consequences (such as poorer health because you didn't go to the gym). In theory, to beat akrasia you only need to bind yourself for whatever the horizon on “immediate” is.
Based on a study of grocery-buying habits — when buying groceries online for delivery tomorrow people buy more ice cream and fewer vegetables than when they’re ordering for delivery next week — and raw guesswork (so far, though backed up by years of experience now!), we’re taking that "akrasia horizon" to be one week. We've found it's been pretty powerful and helpful to our users over the years!
Keywords: time horizon beyond which you can change your goal, dotted vertical line on the graph