CIPM Expert Level candidates must know what return calculations are required by the Global Investment Performance Standards (GIPS(r)), and in which circumstances. 

Most of the time, time-weighted return (TWR) is required, but in some cases a since inception internal rate of return (SI-IRR) must be used. 

But what are the specifics?  Here is a breakdown:

• Generally speaking, i.e., if the real estate provisions of GIPS and the private equity provisions of GIPS do not apply (sections I.6 and I.7, respectively), then time-weighted returns are required by GIPS provision I.2.A.2.
• Total returns (i.e., that include gain/loss and income/expense) must be used (provision I.2.A.1).
• Either gross-of-fees or net-of-fees may be used, as long as clearly labelled (provision I.5.A.1.b).
• Gross is recommended (provision I.5.B.1).

• If the private equity provisions of GIPS (section I.7) apply, then since-inception internal rate of return is required (provision I.7.A.3).
• Total returns (i.e., that include gain/loss and income/expense) must be used (provision I.2.A.1).
• Both gross-of-fees and net-of-fees must be presented (provision I.7.A.21).

• If the real estate provisions of GIPS apply (section I.6), then time-weighted returns are required (provision I.2.A.2).
• In addition to total returns (which reflect gain/loss and income/expense) required by provision I.2.A.1), component returns must be presented (provision I.6.A.9).  Component returns are the capital return (gain/loss) and the income return (income/expense).
• Either gross-of-fees or net-of-fees may be used, as long as clearly labelled (provision I.6.A.14).

• If the composite in question is a closed-end real estate composite, then both time-weighted returns and since inception internal rates of return must be presented.
• For closed-end real estate composites,  with respect to time-weighted returns, the general requirements for real-estate composites must be met; i.e., calculation of total return, capital return and income return, which may be shown either gross- or net-of-fees (provisions I.2.A.2, I.2.A.1, I.6.A.9 and I.6.A.14).
• Firms must present the net-of-fees since-inception internal rate of return (provision I.6.A.23).
• If the firm shows gross-of-fees since inception internal rate of return, it must be shown for the same periods ;for which the net-of-fees SI-IRR is presented.

So, as you can see, it can become a bit involved when trying to determine whether to use TWR or SI-IRR, what is required vs. what is recommended, and is it a net- or gross-of-fees return that should or must be used.  The above bullets should spell out all of the scenarios.

Hope this helps!