TY - STAND AU - A. Dregan AU - A. Grieve AU - T. Van Staa AU - M. Gulliford BT - BMC Med Res Methodol DO - 10.1186/1471-2288-11-168 PY - 2011 EP - 168 T2 - BMC Med Res Methodol TI - Potential application of item-response theory to interpretation of medical codes in electronic patient records VL - 11 SN - 1471-2288 ER -