I have two groups S(story) and P(picture).

Each is composed of the same 48 subjects.

My endpoint is a 'score' on an ordinal 4 point scale.

The 48 subjects create varying number of stories. Each story is graded on that four point scale. Some subjects made 2 stories. Some made 6. The stories were split between 7 reviewers and each had to only grade 1 (this is time intensive). So each subject has between 2 and 6 scores.

The 48 subjects also create one picture. This picture is graded on the same scale and can be done quickly. All 7 reviewers grade each picture. So each subject has seven scores in this group.

Now my question is how on earth do I compare the scores from S to P.

Is it some type of 2-way repeated measures nonparametric test with a lot of missing data?

I'm really lost on what I should do and how I can achieve it in SPSS.

Thanks for any help!