David R. MacIver, mathematician, programmer, and long-time Beeminder fan, posted an ingenious idea to the Beeminder forum recently. We liked it so much we built it in as an option for custom graphs and convinced David to blog about it. This is crossposted on David’s blog.
One of my vices is that I drink a bit too much. Not to the level where I have a problem, but it would be strictly better if I cut out about 2 or 3 of the drinks I have in a typical week. This seems like an obvious use case for Beeminder.
I’ve previously beeminded units of alcohol consumption and concluded that, measured as a total number of units per week, I’m completely fine. The recommended maximum intake for an adult male is somewhere in the region of 20 - 25 units per week depending on who you ask. When I was beeminding this regularly I never had trouble keeping under 12 units. I drink a bit more than that now, but nowhere close to twice as much.
So if I’m that far under the recommended guideline why do I think I drink too much?
Well, the low average is because I actually have a lot of nights of any given week where I don’t drink at all. The problem is that on nights that I do drink I often have a drink or two more than I should. I make tasty cocktails, and if I’ve just had a cocktail I really liked then making another one sounds like an excellent idea. By the third drink of the evening I will usually discover the next day that it wasn’t such an excellent idea.
So what I need is a Beeminder goal that matches the structure of the behaviour I want to change: I need a way to beemind the peaks as well as the averages. A week with two three-drink nights should “cost” more than a week with a single drink every night.
I’ve come up with what seems like a good structure for this.
The idea is to assign each drink  a number of points. The first drink in a day costs one point, the second two, the third three, and so on. Because these add up, this means that a day with one drink costs one point, a day with two drinks costs three, a day with three drinks costs six. It mounts up pretty quickly. These running totals are called triangle numbers, hence the title of this post.
To start with I’ve capped the total number of points at 15/week. This is a deliberately lax starting rate which equates to a maximum of 11 drinks in a week (3 days with 1 drink and 4 with 2). Since the drinks I tend to have are two units this is about at the recommended maximum. Note that I can hit the limit while drinking less than that: If I have more than two drinks on any night, the extra points mean I’m forced  to reduce the total for the rest of the week to compensate.
Example permitted maximum drinking patterns:
Note that 3 days with 3 drinks is not permitted even with the remaining rest of the week free: That would be 18 points which would take me over the threshold .
I was originally planning to track this manually, but then Danny got so excited by the concept that he added a feature for it, so it’s easy to give this a try yourself:
Best to apply this to a fresh goal. This stuff can easily screw up your goal if you’re not careful, so don’t do it to one with data you care about. 
If you want to track it manually instead, just enter the numbers yourself: 1 for the first drink, 2 for the second, and so on . A standard Do Less goal will sum those up, yielding the triangular numbers.
So far this is experimental. I’ve only been running this for a few days, so it may turn out to be a silly idea in the long run. I don’t think it will though. I’m quite pleased with the incentive structure it sets up, and the effect so far has definitely been to make me think more carefully about the later drinks. I’ll add a follow up comment to this post in a month or so when I’ve had time to see how it works.
UPDATE: Follow-up on the forum.
 Drinks, not units of alcohol. I try to keep my Beeminder goals based on things I don’t need to estimate or measure. Especially if I have to estimate them after a few drinks. Most of my drinks are approximately two units as I tend to drink cocktails or spirits.
 Well, “forced”. I have this goal set up so that it’s OK to fail occasionally. I’ve got a pledge cap of $10 set, so the worst case scenario is that my drinks suddenly become a bit more expensive. This is coupled with a no-mercy recommit: If I decided last night that I was OK derailing, I’m not off the hook today. This is based on a concept from Bethany Griswold about using Beeminder to make free things not free. The Bethany better known in these parts makes a related point in “Be Nice To Yourself”.
 Normally this wouldn’t be quite true because I could build up buffer from week to week if I wasn’t drinking much, but I’ve got this goal set to auto-ratchet so I can’t actually do that. If I build up more than a week of buffer it cuts back down to a week. Another terrifyingly advanced premium feature, available with Plan Bee.
 Danny here: But we’re excited about people trying this so actually please do feel free to experiment and holler at firstname.lastname@example.org if you break something and we’ll fix it!
 Danny doesn’t like this because it breaks the “Quantified Self First” principle. The numbers that you enter this way don’t correspond directly to something you want to measure.  Personally I’m much more interested in behaviour change than QS, so I don’t have a problem with it.
 Danny again: Actually, QS is more about measuring real-world things. With the triangle aggregation, we’ve got the best of both worlds. We get a true count of the number of drinks (real-world measure) and we get a goal-friendly aggregation for beeminding. You can export the data and do something else with it or change the aggregation function back to normal summing if you want to go back to beeminding total amount of alcohol consumed.
UPDATE: Discussion continues in the forum thread that spawned this post…
Image credit: Philip Tibbetts