The definition of S_DISC_U differs by HCUP database:

• For the NIS prior to 2012, S_DISC_U contains the total number of inpatient discharges in sampled hospitals for the stratum.
• For the NIS beginning in 2012, S_DISC_U contains the total number of inpatient discharges for the stratum.
• For the NRD, S_DISC_U contains the total number of inpatient discharges for the stratum.
• For the NEDS, S_DISC_U contains the total number of ED visits in sampled hospital-based emergency departments for the stratum.
• For the NASS, N_DISC_U contains the total number of major ambulatory surgery encounters in sampled hospital-owned facilities for the stratum.