Traditionally, collisional rate coefficients for electron impact excitation or ionization of an ion in a plasma are obtained by first computing a binary collision cross section σ(v) between a single plasma electron and an isolated ion. This quantity is subsequently averaged over the plasma electron flux to obtain the rate coefficient 〈vσ(v)〉. In a dense plasma this binary collision picture breaks down. A model is presented in which the collisional rate coefficient due to many interacting plasma electrons are computed directly, without reference to a binary cross section. Focus is directed toward dynamical screening in electron impact ionization of hydrogenic ions.