In HBR this month, Paul Saffo discusses Six Rules for Effective Forecasting - it's an interesting article, and I like the way he separates "forecasts" from "predictions" (which we sometimes have to do when managers tell us we can't workforce plan, because it's impossible to "predict" the future):
Unlike a prediction, a forecast must have a logic to it. That’s what lifts forecasting out of the dark realm of superstition. The forecaster must be able to articulate and defend that logic. Moreover, the consumer of the forecast must understand enough of the forecast process and logic to make an independent assessment of its quality—and to properly account for the opportunities and risks it presents. The wise consumer of a forecast is not a trusting bystander but a participant and, above all, a critic.

Notice the focus on the consumer of the forecast - a participant and a critic, who understands the forecast process and logic. This is a critical aspect of successful strategic planning - that it is done with the business, not for them. In fact, we strongly advocate that the business themselves do the work, and HR own and facilitate the framework itself.

The article goes on to a rich discussion about uncertainty and forecasting, and although the examples it uses are business not workforce based, you might find it quite inspiring - or, like all good articles, you might disagree! The part that raised an eyebrow for me was Rule 5: Look Back Twice as Far as You Look Forward. Often planners, and especially operational workforce planners, depend too much on what happened in the past as predictors of what will happen in the future.

Especially in times of change (like today's global talent market), relying on the past to determine the future can be dangerous, as Saffo acknowledges:
The hardest part of looking back is to know when history doesn’t fit. The temptation is to use history (as the old analogy goes) the way a drunk uses a lamppost, for support rather than illumination. That’s the single worst mistake a forecaster can make, and examples, unfortunately, abound.
For me, the key takeaways of the article for workforce planners are:
  1. Consciously incorporate the exploration of uncertainty into your work - too often we plan only for things that we know
  2. The business is a participant, not just a customer, of workforce planning
  3. The past is not always a good way of predicting the future, especially in times of uncertainty

And above all else, read non-HR (and even non-business!) content to become a more strategic workforce planner.