No, this is not a Hakuna Matata mashup song featuring Ratatouille.
It's the answer to a problem I've had recently as I've been re-reading my 4- and 5-stars from the past: some of them aren't as great this time around, in which case I edit to 3 stars. But I still want to know that these poor demoted books used to be the bees' knees to me, so I've been recording the rating change in a note on each item.
I've been following a consistent format for these notes in order to make them easily findable, e.g. Downgraded rating from 4 to 3. So I figured it would make sense to parse them into the data.
So now rating_change is in the parsed output, along with a date if you want to date your rating changes. (By default, they are dated to the most recent end or start date of the item.)
And so my reading page has a new "demoted list" at the very bottom!
Along with that, previous ratings can be used as a filter in stats queries. Want to know which genres you've changed the most from a 4 or a 5? Run reading "<path to your reading.csv>" "count by genre previous-rating>=4". I thought about adding another filter for specifying rating changes up or down, but decided it was unnecessary because all of my rating changes are downward, except for a single one… which I later reversed 🙃