choremate

choremate is a simple application for tracking the sequence of occasions on which a task is completed and predicting when the next completion will likely be needed.

Usage

When a chore is completed for the first time, ChoreMate records the user provided datetime of the completion as the last completion datetime. Thereafter, when a chore is completed, ChoreMate first prompts for the datetime the chore was actually completed and then prompts for the datetime that the chore actually needed to be completed. Normally these would be the same and, if this is the case, the user can simply press Enter to accept the completion datetime as the value for the needed datetime as well.

But the completion and needed datetimes are not necessarily the same. If, for example, the chore is to fill the bird feeders when they are empty, then the completion datetime would be when the feeders are filled, but the needed datetime would be when the feeders became empty. Suppose I noticed that the feeders were empty yesterday at 3pm, but I didn't get around to filling them until 10am today. Then I would enter 10am today as the completion datetime in response to the first prompt and 3pm yesterday in response to the second prompt. Alternatively, if I'm going to be away for a while and won't be able to fill the bird feeders while I'm gone and they are currently half full, then I might fill them now in the hope that they will not be emptied before I return. In this case I would use the current moment as the completion datetime. But what about the needed datetime? Entering a needed datetime would require me to estimate when the feeders would have become empty. While I could do this, I could also just enter "none". Here's how the different responses would be processed by ChoreMate:

1. Both completion and needed datetimes are provided (but will be the same if the user accepts the default):

   a. the interval needed_completion - last_completion is added to the list of completion intervals for this chore.

   b. from this list of completion intervals, the mean (average) and two measures of dispersion about the mean are calculated and used to forecast the next completion datetime and to determine the "hotness" color of the chore in the list view.

   c. last_completion is updated to the value of the submitted completion datetime to set the beginning of the next interval. The mean interval is added to this datetime to get the forecast of the next completion datetime.

2. A completion datetime and "none" are provided:

   a. skipped

   b. previous mean and dispersion measures are unchanged

   c. last_completion is updated to the value of the submitted completion datetime to set the beginning of the next interval. The mean interval is added to this datetime to get the forecast of the next completion datetime.

Submitting "none" for the needed datetime can be used when the user can't be sure when the completion was or will be needed.

When a chore is completed, ChoreMate records the interval between this and the previous completion and then updates the value of the last completion. The updated last completion is displayed in the last column of the list view. The mean or average of the recorded intervals for the chore is then added to the last completion to get a forecast of when the next completion will likely be needed. This forecast is displayed in the next column of the list view. The chores in list view are sorted by next.

How good is the next forecast? When three or more intervals have been recorded, ChoreMate separates the intervals into those that are less than the mean interval and those that are more than the mean interval. The average difference between an interval and the mean interval is then calculated for each of the two groups and labeled mad_less and mad_more, respectively. The column in the list view labeled +/- displays the range from next - 2 × mad_less to next + 2 × mad_more. The significance of this value is that at least 50% of the recorded intervals must lie within this range - a consquence of Chebyshev's inequality.

The chores are diplayed in the list view in one of seven possible colors based on the current datetime. The diagram below shows the critical datetimes for a chore with |'s. The one labeled N in the middle corresponds to the value in the next column. The others, moving from the far left to the right represent offsets from next: next - 4 × mad_less, next - 3 × mad_less, and so forth ending with next + 4 × mad_more. The numbers below the line represent the Color number used for the different intervals.