What the difference between accrual biases and cash biases ?

A major accounting method that recognizes revenues and expenses at the time physical cash is actually received or paid out. This contrasts to the other major accounting method, accrual accounting, which requires income to be recognized in a company's books at the time the revenue is earned (but not necessarily received) and records expenses when liabilities are incurred (but not necessarily paid for).

For example, let's say a construction company secures a major contract in a given year, but will only be paid for its efforts upon completion of the project. Using cash basis accounting, the company will only be able to recognize the revenue from its project at its completion, while it will record the project's expenses as they are being paid out. 

One of the accounting principals is the Matching Principal.

This means reporting of whatever income earned during the reporting period as well as all related expenses incurred to recognize this revenues.