# Negative binomial v. ZINB: Plot probabilities

3 messages
Open this post in threaded view
|

## Negative binomial v. ZINB: Plot probabilities

 Good morning SPSS gurus!   We have an analysis using a propensity score (likely to be in inEMPS) split into quintiles to compare inEMP=1 to inEMPS=0. We have run a Negative Binomial due to over-dispersion—but a question has been raised about why not a zero-inflated NB.   I have run both (using LOGISTIC and STATS_ZEROINFL) both overall and separately (split file for NB/select if in quintile for ZINB). Now the question is: Which is better?  Since the AIC is only slightly lower for ZINB (around 30/>18000), I’ve been asked to “plot fitted probabilities of the observed data under the zero-inﬂated and the non-zero inﬂated model against each other”   I hope someone can help me with the (best) way to get these plots (within quintile) for NB and ZINB.  This is my first attempt at ZINB.    Here is the syntax I used for both   *** ZERO INFLATED NEGATIVE BINOMIAL USING nBH_EDPre (NUMBER of PRE ED visits). STATS ZEROINFL MODELSOURCE=ESTIMATE DEPENDENT=nBH_EDPOST COUNTMODEL=inEMPS LR3pred nBH_EDPRE   SAMEREGRESSORS=YES   COUNTDIST=NEGBIN ZEROLINK=LOGIT   /OPTIONS STARTVALUES=GENLIN OPTMETHOD=BFGS MAXITER=1000 TOL=0.0000000001   /SAVE DATASET=ZI_NB_n   ID=CID   WORKSPACEACTION=CLEAR.   **************************. ****  With N Pre. **************************. LOGISTIC REGRESSION VARIABLES AnyBH_EDPOST   /METHOD=ENTER inEMPS   /METHOD=ENTER inEMPS nBH_EDPRE   /PRINT=GOODFIT CI(95)   /CRITERIA=PIN(0.05) POUT(0.10) ITERATE(20) CUT(0.5).   -------------- Melissa Ives   This correspondence contains proprietary information some or all of which may be legally privileged; it is for the intended recipient only. If you are not the intended recipient you must not use, disclose, distribute, copy, print, or rely on this correspondence and completely dispose of the correspondence immediately. Please notify the sender if you have received this email in error. NOTE: Messages to or from the State of Connecticut domain may be subject to the Freedom of Information statutes and regulations. ===================== To manage your subscription to SPSSX-L, send a message to [hidden email] (not to SPSSX-L), with no body text except the command. To leave the list, send the command SIGNOFF SPSSX-L For a list of commands to manage subscriptions, send the command INFO REFCARD