Rather than all nucleons experiencing some modification, the short-range correlations hypothesis predicts that most nucleons at any one time are unmodified, but some are substantially modified. The most heavily modified nucleons are those in temporary short-range correlated (SRC) pairs. It has been observed that approximately 20% of nucleons (in medium and heavy nuclei) at any given moment are part of short-lived pairs with significant spatial overlap with a partner nucleon.