The column tjc_observed_28 in the data file joint_exam_deep has values greater than 28 in it. The data dictionary says, “Number of tender joints (out of 28)”. Are values greater than 28 expected?

Yes, they may occur in the data. Quantitative and qualitative assessments of joint swelling and tenderness are found within the JOINT_EXAM and JOINT_EXAM_DETAILS tables, respectively. The joint count may be described in multiple formats including a 28 joint count for swelling and tenderness (variables ‘SJC_OBSERVED_28’ and ‘TJC_OBSERVED_28’) and a total joint count for swelling and tenderness (variables ‘SJC_OBSERVED’ and ‘TJC_OBSERVED’) that includes joints evaluations of 28, 42, 44, or 76 joints. The total number of evaluated joints (e.g, swollen, tender, or normal/not affected) may not be included/known. Availability of the Joint Exam tables depends on the dataset.