How do I get Windows 8 to measure startup impact?

I did an inplace upgrade from Windows 7 Ultimate to Windows 8 Pro, and am just getting used to Windows 8. Under the Task Manager → Startup tab, I see there's an option showing "start up impact".

Despite few reboots, the impact is still in "Not measured" state. What should I do to get Windows to measure this report the impact to me?

This could happen with some of the third party apps where windows is unable to determine the impact.

You can either leave it unrecognized or can try with third party measurement app like Tune Up Utilities.

I suggest you to leave it unrecognized if it doesn't matter a lot to you.