Table 2.

Total number of violations of required research practices per study, for publications in 2015–2016 using the National Inpatient Sample.

Number of violations of required practices	Overall (N = 120)	Journal impact factor <10 (N = 96)	Journal impact factor ≥10 (N = 24)	Estimates for the universe of NIS studies, N=1082*
	Number (%) of studies			Projected number of studies (95% CI)	Projected percentage of studies (95% CI)
0	18 (15.0%)	10 (10.4%)	8 (33.3%)	114 (50 to 177)	10.5% (4.7 to 16.4)
1	28 (23.3%)	21 (21.9%)	7 (29.2%)	229 (143 to 315)	21.2% (13.2 to 29.1)
2	36 (30.0%)	32 (33.3%)	4 (16.7%)	342 (244 to 440)	31.6% (22.6 to 40.7)
3	30 (25.0%)	25 (26.0%)	5 (20.8%)	269 (178 to 360)	24.9% (16.5 to 33.3)
≥4	8 (6.7%)	8 (8.3%)	0 (0.0%)	85 (28 to 142)	7.8% (2.5 to 13.1)

P value = 0.025 (Chi-square test for comparison of studies in journals with impact factor <10 vs ≥10)

^*Results reflect weighted estimates that applied to all studies using NIS data during the study period. An additional estimated 43 studies (95% CI 2 to 85) or 4.0% (95% CI 0.2% to 7.8%) correspond to the 5 studies excluded for using the NIS as a secondary source of data.

NIS, National Inpatient Sample