What to write down for every bet

Date, sport, market, side, the number, the price you took, the stake, and the closing price. Eight fields, thirty seconds, and it is the difference between a record and a memory.

The win-loss column is dominated by variance at any horizon short enough to actually review. Closing line value is not, so without the price at bet time there is nothing in the log that carries information at short horizons.

It also makes review possible at all. Sorting by sport, by market or by price band frequently shows that all the profit came from one segment and everything else was noise around zero.

The problem arrives next. Human memory of prices is selective in a consistent direction: the ones remembered are the ones that felt good, so an unlogged record always reads better than it was.

What to do with it. Start with the next bet. A log that begins today is worth more than a reconstruction of the last year.