What is IRR and how does that differ from the TWRR that we use for public investments?

Internal Rate of Return (IRR) focuses on specific projects or investments, while Time-Weighted Rate of Return (TWRR) focuses on the entire portfolio. The IRR is an annualized measure of return over the life of an investment. IRR is calculated by determining the value at which cash flows must be discounted to have the present value of the asset equal to the price paid for that asset; put more simply, it is an annual growth rate that takes into account the timing of cash flows to and from a fund, which are less predictable in private markets. The TWRR is a method used to calculate the average rate of return of a portfolio over a specific period.