I really appreciate some advise on handling missing values.

Briefly, subjects rated 21 objects (obj 1 ...obj 21) on 14 attributes (attr1...attr14). Given the size of the questionnaire (21*14), we split the questionnaire into two parts:

N1 (about 150) subjects rated Obj1..Obj11 on all 14 attributes.

N2 (about 120) subjects rated Obj12...Obj 21 on all 14 attributes.

Both N1 and N2 come from the same population (based on Ch-squared tests on different demographic variables).

Our Goal: Perform Exploratory factor Analysis and obtain factor scores on all 21 Objects.

My questions are:

Q1. I basically need a complete correlation matrix (21 objects * 14 attributes). About 50% of the data is missing. What kind of imputation should I use to generate the other 50% of missing data?

Q2. Can you recommend a text or journal article which discusses modern missing data analysis procedures - I'm OK with linear algebra and basic stat concepts and can handle notation?

Q3. Can you point me to a programming manual/tutorial for SPSS?

thanks in advance,

statpuzz