Well that's what this post is for. To revive factor development. With the upcoming Asian data (did you pledge? few days left!) and our upcoming "Factor Miner", all these new factors and permutations can be properly tested.
BTW, the task to add ROIC (and several other ratios) was first added 5 years ago in our Jira. It was labelled with high importance and has been bounced around. No use in pointing fingers since most of the people responsible have left. But one of the reasons is the complications. For example NOPAT in "textbooks" uses the corporate tax rate. But our Jira task wants the sector average (not sure why). This makes the task a lot more difficult since we currently do not pre-compute sector averages (what universe, cap avg or median, etc.), so the entire task just gets moved around like a hot potato.
And, maybe, these tax adjustments are a complete waste of time when tested for IC. What if the strongest IC comes from buying the highest ROIC from every sector? The tax component of the formula gets completely canceled out, as well as all the effort that went into it.
Lastly, this "sector tax rate" is far from stable. Run this screen
FOrder("MktCap", #Sector, #DESC, true) = 1
This gives you the top stock in each sector by MktCap. Then click on any of them, and go to the fundamental chart. Start a new chart and enter this formula
Aggregate("TxRate%TTM", #Sector, #CapAvg,16.5,#Exclude,false,true)
Scroll though the charts and tell me if it makes any sense to use it!? I don't see it. If the IC is confirmed we will use it. If not a simpler, less noisy version of ROIC is what's best for P123.