Table 3.
Rate of violations of required research practices for publications in 2015–2016 that used the National Inpatient Sample.
| Research Practice No. |
Required Research Practices |
Overall (N = 120) |
Estimates for the universe of NIS studies (N = 1082) |
Impact factor <10 (N = 96) |
Impact factor ≥10 (N = 24) |
P-value* (Fisher’s exact test) |
||||
|---|---|---|---|---|---|---|---|---|---|---|
| Studies violating practice, n (%) |
Eligible, N |
Projected number of studies (95% CI) |
Projected percentage of studies (95% CI)† |
Studies violating practice, n (%) |
Eligible, N |
Studies violating practice, n (%) |
Eligible, N |
|||
| 1 | Identifying observations as hospitalization events rather than unique patients | 45 (37.5%) | 120 | 437 (334 to 541) | 40.4% (30.9 to 50.0) | 41 (42.7%) | 96 | 4 (16.7%) | 24 | 0.02 |
| 2 | Not performing state-level analyses | 10 (8.3%) | 120 | 77 (23 to 131) | 7.1% (2.1 to 12.1) | 7 (7.3%) | 96 | 3 (12.5%) | 24 | 0.42 |
| 3 | Limiting hospital-level analyses to data from years 1988–2011 | 2 (11.8%) | 17 | 12 (0 to 33) | 8.2% (0.0 to 22.5)‡ | 1 (7.7%) | 13 | 1 (25.0%) | 4 | 0.43 |
| 4 | Not performing physician-level analyses | 3 (2.5%) | 120 | 32 (0 to 68) | 2.9% (0.0 to 6.2) | 3 (3.1%) | 96 | 0 (0.0%) | 24 | 1.0 |
| 5 | Not using non-specific secondary diagnosis codes to infer in-hospital events | 62 (51.7%) | 120 | 588 (484 to 693) | 54.4% (44.7 to 64.0) | 55 (57.3%) | 96 | 7 (29.7%) | 24 | 0.02 |
| 6 | Using survey-specific analysis methods that account for clustering, stratification and weighting | 79 (65.8%) | 120 | 739 (642 to 837) | 68.3% (59.3 to 77.3) | 69 (71.9%) | 96 | 10 (41.7%) | 24 | 0.008 |
| 7 | Accounting for data changes in trend analyses spanning major transition periods in the dataset (1997–1998 and 2011–2012) | 21 (77.8%) | 27 | 174 (97 to 251) | 79.7% (62.5 to 97.0)§ | 16 (80.0%) | 20 | 5 (71.4%) | 7 | 0.63 |
For comparison of studies in journals with impact factor <10 vs ≥10
Unless otherwise specified, results reflect estimated percentage of all 1082 studies using NIS data during the study period with a given violation. Therefore, an estimated 43 studies (95% CI 2 to 85) that correspond to the 5 studies excluded for using the NIS as a secondary source of data, are represented in the denominator for these percentages.
Percentage of the estimated 141 studies performing hospital-level analyses. These studies correspond to the 17 sampled studies that performed these analyses.
Percentage of the estimated 218 studies performing analyses spanning major data transitions. These studies correspond to the 17 sampled studies that performed these analyses.
NIS, National Inpatient Sample