Yep, that's why I included the post date in the information available to the model; in theory (if it's smart enough) it should be able to take that into account

Yep, that's why I included the post date in the information available to the model; in theory (if it's smart enough) it should be able to take that into account. That said I didn't include time-of-day; it would be interesting to see whether adding that information would be able to make the model more accurate! If the reward model is indeed smart enough to be able to take that into account you could actually use it to plan the optimal time of day to post a specific story! You could just use the reward model to compute a predicted score for 8 different versions of your content, holding the post title/text constant across them all and just changing the date. Based on the differences in scores, you can determine which posting time the RM thinks is most likely to make your post successful!