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My Per Developer Timelines stretch across a wide range of dates. How can I steepen this slope?

long slope

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1 Answer

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There's an elephant in the room.

It's very likely that you have one or more cases with a large estimate (over 40 hours).

When we predict your ship dates, we run a bunch of simulations. An elephantine estimate injects a huge amount of variability into this process, because one thing matters more than everything else:

Which "velocity" was applied to that big estimate for this simulation

Here's a simplified example:


Let's say you have two cases with estimates:

Let's say you have these two estimates in your history:

  • estimated: 1hr, actual: 30m (You finished in half the time.)
  • estimated: 1hr, actual: 2hr (It took twice as long as thought.)

These two estimates translate into two velocities:

  • 0.5
  • 2

When we apply the first velocity to a case in EBS, we expect the case to take half as long as its estimate. When we pick the second, we expect it to take twice as long.


Simulation 1

  • Update Logo draws 2, so: 1hr * 2 = 2hrs
  • Rewrite code from scratch draws 0.5, so: 40hrs * 0.5 = 20hrs

    Total: 22 hours


Simulation 2

  • Update Logo draws 0.5, so: 1hr * 0.5 = 0.5hrs
  • Rewrite code from scratch draws 2, so: 40hrs * 2 = 80hrs

    Total: 80.5 hours


So it's either going to take half a week or two full weeks.

Now, let's break up that big case into five smaller cases, each representing a day of work.

  • Update Logo - 1 hr
  • Investigate rewriting from scratch - 8 hrs
  • Convince mgmt it's a bad idea - 8 hrs
  • Find bugs - 8hrs
  • Fix them - 8hrs
  • Hit the beach - 8hrs

Same number of total estimated hours. Different breakdown.


Simulation 1

  • 1hr * 0.5 = 0.5hrs
  • 8hrs * 2 = 16hrs
  • 8hrs * 0.5 = 4hrs
  • 8hrs * 2 = 16hrs
  • 8hrs * 0.5 = 4hrs
  • 8hrs * 2 = 16hrs

    Total: 56.6 hours


Simulation 2

  • 1hr * 2 = 2hrs
  • 8hrs * 0.5 = 4hrs
  • 8hrs * 2 = 16hrs
  • 8hrs * 0.5 = 4hrs
  • 8hrs * 2 = 16hrs
  • 8hrs * 0.5 = 4hrs

    Total: 46 hours


This is a very simplified example, but as you can see, the spread between the high and low estimates is greatly reduced by breaking up cases into smaller increments.

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