The RCT is free to access (if you haven't downloaded more than three NBER papers; if you have, open the page in a different browser). Scroll down on the page I linked and download it via the button.

Statistically, you can control for variables in OLS regression--that's literally exactly what the model does when you include more than one variable--and, provided that you got your doctorate in anything that uses statistics, I am sure you know that.

Seasonality is one of the more basic economics concepts. The influence of weather and seasonal illness trends on productivity has been shown in a number of studies (e.g., productivity declines during the flu season). The authors didn't "show" it because it would be like showing gravity in a physics paper. Some things can be assumed. Also, productivity didn't have a trend, as was stated in the text that I quoted.

You completely ignored the log transformed results, which the authors note were better fit by the regression than the untransformed data, and which showed less productivity in work from home regardless of whether seasonality was controlled.

Personally, I think people should be able to work from home all they want. Productivity isn't the only important thing in life, nor is it the only important thing to businesses (e.g., retention of top employees is important). I am wholly against WebMD and all other companies requiring employees to return to the office. All I was doing in my comments was trying to clarify the data on WFH and productivity. There are good reasons to continue to allow WFH, but increased productivity is not one.

I'm going to finish my course prep. You can have the final word here; I don't have time to continue debating anymore.