added Eng Scoping section to PFP

content/departments/engineering/product-planning.md

@@ -10,7 +10,8 @@ as a company in our strategy and roadmap.
 
 It's the product teams – engineering and product together – that have the
 expertise, context and pride of ownership to be best suited to propose the
-highest impact work that fits those goals.
+highest impact work that fits those goals. And they're the team that can do
+the correct [eng scoping](#engineer-scoping).
 
 Per-team planning reviews are where we come together to ensure we're happy with
 where we're headed at each planning cycle. TPMs will pull together reviews for
@@ -43,3 +44,23 @@ or another review meeting will be scheduled to follow up until there is alignmen
 
 Note, not every team will have work to do that applies to every goal every
 quarter. Likewise, not every work item is expected to meet a strategic goal.
+
+## Engineer Scoping
+For any launch, we have a finite amount of time and a finite number of engineers.
+After EPD has laid out their hopes and dreams for a given launch but before the
+PFP review itself, EPD should go through an "eng scoping" exercise, i.e.
+1. What is the eng effort associated with each of the P0 and P1 items, e.g. 2
+days or 3 weeks or ...? [Here's an example of one such exercise.](https://docs.google.com/spreadsheets/d/1adlwcMWHIpDGioBkE9LUdLMHxprtxhh_WSZqxu6Iyxs/edit#gid=0)
+1. Given the priorities and the eng effort required for each item, where do we
+draw the line of what we can accomplish for our launch? Ideally it includes all
+of the P0s. If it doesn't, we have to mitigate.
+1. Mitigate the implications of the where the line between what we need (P0s),
+what we want (P1s) and our actual eng effort. Can we get all of the P0s in?
+If not, then what do we do? Continue cutting scope? Slip the release?
+
+The eng scoping work is the difference between eyeballing a list of requirements
+and hoping we can get them all done and actually having some confidence that
+we can accomplish what we want. And if we can't, we want to know that ASAP so
+that we can escalate as part of the PFP review in the Risks/Needs section
+of the PFP review.
+