Hi, I tried fitting loglinear model using the glm(catspec). The data used is FHtab. . An independence model was fitted. Here summary() and fitmacro( ) give different values for AIC. I understand that fitmacro( ) takes the likelilhood ratio L2(deviance) to calculate AIC and uses the formula AIC= L2- d.f(deviance)*2 and this AIC is used for comparison of nested models. (Am I right?) The value given by loglik( ) is used by summary() to calculate AIC in the formula AIC= -2 logL + K* e.d.f. Can anybody tell me how this log L is calculated? It is not logL=Sum(ni* log (pi)), where pi= fitted frequency / total no. of observations. The help available at extract AIC( ) also is not giving the answer. Please help Thanks Subha gLaunchProfile.stop('RT_RP', false);gLaunchProfile.start('RT_BP');gLaunchProfile.start('LD_JS_BP'); YAHOO.mc.intl = "us";YAHOO.mc.IM_TOGGLE_STRINGS = {"im_settings_helpurl" : "http://help.yahoo.com/l/us/yahoo/mail/classic/chat/","im_settings_help_toggle" : "1","im_enable_mobile_l10n": "1","im_sign_in": "true","im_time_format_am" : "AM","im_time_format_pm" : "PM","im_date_time_format" : "{d}/{M}/{yy} {h}:{mm} {A}"};if (YAHOO.mc.page.generic) {YAHOO.mc.page.generic.initComposeMenu();}YAHOO.mc.page.TriggerULT=true;YAHOO.util.Event.onDOMReady(function () {sessionMgr.initSession();sessionMgr.loadFromBookmarks();});var adPrefetch = true;if (document.getElementById("JSMailOptionsLink")) {document.getElementById("JSMailOptionsLink").href = optionObj["JSMailOptionsLink"];}YAHOO.util.Event.on(["searchTheWebtop", "searchTheWebbottom"], "submit", webSearchHandle);if (document.getElementById("chk_pop_options") || document.getElementById("chk_pop_error") || document.getElementById("option_bad_folder") || document.getElementById("folders_options_spam") || document.getElementById("folders_options_sent") || document.getElementById("spam_edit_options")) {YAHOO.util.Event.addListener(YAHOO.mc.optionsID, "click", displayOptions, optionObj);}YAHOO.namespace("fcue"); YAHOO.mc.FCUE_METADATA = {imInit:"",imSent:"",fcElap:"",fcEcap:"",fcNag:"",inEcap:"",inElap:""};YAHOO.mc.noCues = false;YAHOO.mc.msgrLoaded = false;YAHOO.mc.loadMsgr = function () {clearTimeout(YAHOO.mc.msgrLoadID);if (hasIM && !YAHOO.mc.msgrLoaded) {YAHOO.mc.msgrLoaded = true;YAHOO.util.Get.script("http://mail.yimg.com/d/combo?/mg/5_3_7/js/im_blue_all.js&/mg/5_3_7/js/us_strings.js&/mg/5_3_7/js/msgr.js&ult/ylc_1.9.js");}};YAHOO.util.Event.on(window, "load", YAHOO.mc.loadMsgr);YAHOO.mc.msgrLoadID = setTimeout(YAHOO.mc.loadMsgr, 5000); gLaunchProfile.stop('LD_JS_BP', false); [[alternative HTML version deleted]]