A shell model study of the even parity levels of ¹⁸O and ¹⁸F is made in the light of much recent data. Particular attention is paid to the sensitivity of the results to assumptions regarding the exchange mixture and the shell model potential. Overall agreement with experiment is reasonable. Even when allowance has been made for collective enhancement, however, difficulties remain in understanding certain E2 transition probabilities. A 3⁺ level is predicted in ¹⁸O at an excitation energy of around 5 MeV.