I really like how you're approaching this analytically and how you've decided to conduct an experiment I have seen people are showing concerns about this.
The idea just came to me that you could make a poll to keep track of the ratio. Like this for example maybe:
(whatever title you want): e.g. ratio of related topics to unrelated topics
- 0.0 - 0.1
- 0.1 - 0.2
- 0.2 - 0.3
- 0.3 - 0.4
- 0.4 - 0.5
- 0.5 - 0.6
- 0.6 - 0.7
- 0.7 - 0.8
- 0.8 - 0.9
- 0.9 - 10.0
hmm I realised it won't tell you what day you added the data, but you will know what the stats look like over time. (Or even maybe if you like using spreadsheets, you could put the data into a spreadsheet and share a screenshot as another idea)
Also I see you are gathering data from the same time each day, I think it's great you are thinking about keeping a factor consistent I was maybe thinking then the data will only reflect what topics are updated at around that time of day though, but that is okay I am just sharing some things that are coming to mind. It's lovely that you are open to ideas!
oh, also after Corvus/GysvANDRegulus said, hmm, Aether what do you think would be considered on-topic/related?
edit: oh okay you've answered that hehe
Edit2: I will try to put more of my focus on the conducting of the experiment and looking at the data here, I realised sometimes opinions can influence how you look at things