NIS File Specifications

Each year of the NIS is comprised of the Core Data File and three or more additional files, in ASCII text format. A Hospital Weights File is always included. Severity Measures Files, Diagnosis and Procedure Groups Files, and database 10% Sample files are also included, depending on the year. The following links provide file specifications for the NIS including the dataset name, number of records, and record layout.

2023 NIS
2022 NIS
2021 NIS
2020 NIS
2019 NIS
2018 NIS
2017 NIS
2016 NIS
2015 NIS
2014 NIS
2013 NIS
2012 NIS
2011 NIS
2010 NIS
2009 NIS
2008 NIS
2007 NIS
2006 NIS
2005 NIS
2004 NIS
2003 NIS
2002 NIS
2001 NIS
2000 NIS
1999 NIS, Version 2
1999 NIS, Version 1
1998 NIS, Version 2
1998 NIS, Version 1
1997 NIS
1996 NIS
1995 NIS
1994 NIS
1993 NIS
1992-1988 NIS

2023 NIS

Core File

Data Set Name: NIS_2023_CORE
Number of Records: 6,743,716
Record layout NIS 2023 Core

Hospital Weights File

Data Set Name: NIS_2023_HOSPITAL
Number of Records: 4,181
Record layout NIS 2023 Hospital

Diagnosis and Procedure Groups File

Data Set Name: NIS_2023_DX_PR_GRPS
Number of Records: 6,743,716
Record layout NIS 2023 DX_PR_GRPS

Severity Measures File

Data Set Name: NIS_2023_SEVERITY
Number of Records: 6,743,716
Record layout NIS 2023 Severity

Top

2022 NIS

Core File

Data Set Name: NIS_2022_CORE
Number of Records: 6,578,372
Record layout NIS 2022 Core

Hospital Weights File

Data Set Name: NIS_2022_HOSPITAL
Number of Records: 4,544
Record layout NIS 2022 Hospital

Diagnosis and Procedure Groups File

Data Set Name: NIS_2022_DX_PR_GRPS
Number of Records: 6,578,372
Record layout NIS 2022 DX_PR_GRPS

Severity Measures File

Data Set Name: NIS_2022_SEVERITY
Number of Records: 6,578,372
Record layout NIS 2022 Severity

Top

2021 NIS

Core File

Data Set Name: NIS_2021_CORE
Number of Records: 6,666,752
Record layout NIS 2021 Core

Hospital Weights File

Data Set Name: NIS_2021_HOSPITAL
Number of Records: 4,558
Record layout NIS 2021 Hospital

Diagnosis and Procedure Groups File

Data Set Name: NIS_2021_DX_PR_GRPS
Number of Records: 6,666,752
Record layout NIS 2021 DX_PR_GRPS

Severity Measures File

Data Set Name: NIS_2021_SEVERITY
Number of Records: 6,666,752
Record layout NIS 2021 Severity

Top

2020 NIS

Core File

Data Set Name: NIS_2020_CORE_V2
Number of Records: 6,471,165
Record layout NIS 2020 Core V2

Hospital Weights File

Data Set Name: NIS_2020_HOSPITAL_V2
Number of Records: 4,580
Record layout NIS 2020 Hospital V2

Diagnosis and Procedure Groups File

Data Set Name: NIS_2020_DX_PR_GRPS_V2
Number of Records: 6,471,165
Record layout NIS 2020 DX_PR_GRPS_V2

Severity Measures File

Data Set Name: NIS_2020_SEVERITY_V2
Number of Records: 6,471,165
Record layout NIS 2020 Severity V2

Top

2019 NIS

Core File

Data Set Name: NIS_2019_CORE_V2
Number of Records: 7,083,805
Record layout NIS 2019 Core V2

Hospital Weights File

Data Set Name: NIS_2019_HOSPITAL_V2
Number of Records: 4,568
Record layout NIS 2019 Hospital V2

Diagnosis and Procedure Groups File

Data Set Name: NIS_2019_DX_PR_GRPS_V2
Number of Records: 7,083,805
Record layout NIS 2019 DX_PR_GRPS_V2

Severity Measures File

Data Set Name: NIS_2019_SEVERITY_V2
Number of Records: 7,083,805
Record layout NIS 2019 Severity V2

Top

2018 NIS

Core File

Data Set Name: NIS_2018_CORE
Number of Records: 7,105,498
Record layout NIS 2018 Core

Hospital Weights File

Data Set Name: NIS_2018_HOSPITAL
Number of Records: 4,550
Record layout NIS 2018 Hospital

Diagnosis and Procedure Groups File

Data Set Name: NIS_2018_DX_PR_GRPS
Number of Records: 7,105,498
Record layout NIS 2018 DX_PR_GRPS

Severity Measures File

Data Set Name: NIS_2018_SEVERITY
Number of Records: 7,105,498
Record layout NIS 2018 Severity

Top

2017 NIS

Core File

Data Set Name: NIS_2017_CORE
Number of Records: 7,159,694
Record layout NIS 2017 Core

Hospital Weights File

Data Set Name: NIS_2017_HOSPITAL
Number of Records: 4,584
Record layout NIS 2017 Hospital

Severity Measures File

Data Set Name: NIS_2017_SEVERITY
Number of Records: 7,159,694
Record layout NIS 2017 Severity

Top

2016 NIS

Core File

Data Set Name: NIS_2016_CORE
Number of Records: 7,135,090
Record layout NIS 2016 Core

Hospital Weights File

Data Set Name: NIS_2016_HOSPITAL
Number of Records: 4,575
Record layout NIS 2016 Hospital

Severity Measures File

Data Set Name: NIS_2016_SEVERITY
Number of Records: 7,135,090
Record layout NIS 2016 Severity

Top

2015 NIS

Core File

Data Set Name: NIS_2015_CORE
Number of Records: 7,153,989
Record layout NIS 2015 Core

Hospital Weights File

Data Set Name: NIS_2015_HOSPITAL
Number of Records: 4,573
Record layout NIS 2015 Hospital

Severity Measures File

Data Set Name: NIS_2015Q1Q3_SEVERITY
Number of Records: 5,377,720
Record layout NIS 2015 Q1Q3 Severity

Data Set Name: NIS_2015Q4_SEVERITY
Number of Records: 1,776,269
Record layout NIS 2015 Q4 Severity

Diagnosis and Procedure Groups File

Data Set Name: NIS_2015Q1Q3_DX_PR_GRPS
Number of Records: 5,377,720
Record layout NIS 2015 Q1Q3 DX_PR Groups

Data Set Name: NIS_2015Q4_DX_PR_GRPS
Number of Records: 1,776,269
Record layout NIS 2015 Q4 DX_PR Groups

Top

2014 NIS

Core File

Data Set Name: NIS_2014_CORE
Number of Records: 7,071,762
Record layout NIS 2014 Core

Hospital Weights File

Data Set Name: NIS_2014_HOSPITAL
Number of Records: 4,411
Record layout NIS 2014 Hospital

Severity Measures File

Data Set Name: NIS_2014_SEVERITY
Number of Records: 7,071,762
Record layout NIS 2014 Severity

Diagnosis and Procedure Groups File

Data Set Name: NIS_2014_DX_PR_GRPS
Number of Records: 7,071,762
Record layout NIS 2014 DX_PR Groups

Top

2013 NIS

Core File

Data Set Name: NIS_2013_CORE
Number of Records: 7,119,563
Record layout NIS 2013 Core

Hospital Weights File

Data Set Name: NIS_2013_HOSPITAL
Number of Records: 4,363
Record layout NIS 2013 Hospital

Severity Measures File

Data Set Name: NIS_2013_SEVERITY
Number of Records: 7,119,563
Record layout NIS 2013 Severity

Diagnosis and Procedure Groups File

Data Set Name: NIS_2013_DX_PR_GRPS
Number of Records: 7,119,563
Record layout NIS 2013 DX_PR Groups

Top

2012 NIS

Core File

Data Set Name: NIS_2012_CORE
Number of Records: 7,296,968
Record layout NIS 2012 Core

Hospital Weights File

Data Set Name: NIS_2012_HOSPITAL
Number of Records: 4,378
Record layout NIS 2012 Hospital

Severity Measures File

Data Set Name: NIS_2012_SEVERITY
Number of Records: 7,296,968
Record layout NIS 2012 Severity

Diagnosis and Procedure Groups File

Data Set Name: NIS_2012_DX_PR_GRPS
Number of Records: 7,296,968
Record layout NIS 2012 DX_PR Groups

Top

2011 NIS

Core File

Data Set Name: NIS_2011_CORE
Number of Records: 8,023,590
Record layout NIS 2011 Core

Hospital Weights File

Data Set Name: NIS_2011_HOSPITAL
Number of Records: 1,049
Record layout NIS 2011 Hospital

Severity Measures File

Data Set Name: NIS_2011_SEVERITY
Number of Records: 8,023,590
Record layout NIS 2011 Severity

Diagnosis and Procedure Groups File

Data Set Name: NIS_2011_DX_PR_GRPS
Number of Records: 8,023,590
Record layout NIS 2011 DX_PR Groups

Top

2010 NIS

Core File

Data Set Name: NIS_2010_CORE
Number of Records: 7,800,441
Record layout NIS 2010 Core

Hospital Weights File

Data Set Name: NIS_2010_HOSPITAL
Number of Records: 1,051
Record layout NIS 2010 Hospital

Severity Measures File

Data Set Name: NIS_2010_SEVERITY
Number of Records: 7,800,441
Record layout NIS 2010 Severity

Diagnosis and Procedure Groups File

Data Set Name: NIS_2010_DX_PR_GRPS
Number of Records: 7,800,441
Record layout NIS 2010 DX_PR Groups

Top

2009 NIS

Core File

Data Set Name: NIS_2009_CORE
Number of Records: 7,810,762
Record layout NIS 2009 Core

Hospital Weights File

Data Set Name: NIS_2009_HOSPITAL
Number of Records: 1,050
Record layout NIS 2009 Hospital

Severity Measures File

Data Set Name: NIS_2009_SEVERITY
Number of Records: 7,810,762
Record layout NIS 2009 Severity

Diagnosis and Procedure Groups File

Data Set Name: NIS_2009_DX_PR_GRPS
Number of Records: 7,810,762
Record layout NIS 2009 DX_PR Groups

Top

2008 NIS

Core File

Data Set Name: NIS_2008_CORE
Number of Records: 8,158,381
Record layout NIS 2008 Core

Hospital Weights File

Data Set Name: NIS_2008_HOSPITAL
Number of Records: 1,056
Record layout NIS 2008 Hospital

Severity Measures File

Data Set Name: NIS_2008_SEVERITY
Number of Records: 8,158,381
Record layout NIS 2008 Severity

Diagnosis and Procedure Groups File

Data Set Name: NIS_2008_DX_PR_GRPS
Number of Records: 8,158,381
Record layout NIS 2008 DX_PR Groups

Top

2007 NIS

Core File

Data Set Name: NIS_2007_CORE
Number of Records: 8,043,415
Record layout NIS 2007 Core

Hospital Weights File

Data Set Name: NIS_2007_HOSPITAL
Number of Records: 1,044
Record layout NIS 2007 Hospital

Severity Measures File

Data Set Name: NIS_2007_SEVERITY
Number of Records: 8,043,415
Record layout NIS 2007 Severity

Diagnosis and Procedure Groups File

Data Set Name: NIS_2007_DX_PR_GRPS
Number of Records: 8,043,415
Record layout NIS 2007 DX_PR Groups

Top

2006 NIS

Core File

Data Set Name: NIS_2006_CORE
Number of Records: 8,074,825
Record layout NIS 2006 Core

Hospital Weights File

Data Set Name: NIS_2006_HOSPITAL
Number of Records: 1,045
Record layout NIS 2006 Hospital

Severity Measures File

Data Set Name: NIS_2006_SEVERITY
Number of Records: 8,074,825
Record layout NIS 2006 Severity

Diagnosis and Procedure Groups File

Data Set Name: NIS_2006_DX_PR_GRPS
Number of Records: 8,074,825
Record layout NIS 2006 DX_PR Groups

Top

2005 NIS

Core File

Data Set Name: NIS_2005_CORE
Number of Records: 7,995,048
Record layout NIS 2005 Core

Hospital Weights File

Data Set Name: NIS_2005_HOSPITAL
Number of Records: 1,054
Record layout NIS 2005 Hospital

Severity Measures File

Data Set Name: NIS_2005_SEVERITY
Number of Records: 7,995,048
Record layout NIS 2005 Severity

Diagnosis and Procedure Groups File

Data Set Name: NIS_2005_DX_PR_GRPS
Number of Records: 7,995,048
Record layout NIS 2005 DX_PR Groups

Top

2004 NIS

Core File

Data Set Name: NIS_2004_CORE.ASC
Number of Records: 8,004,571
Record layout NIS 2004 Core

Hospital Weights File

Data Set Name: NIS_2004_HOSPITAL.ASC
Number of Records: 1,004
Record layout NIS 2004 Hospital

10% Sample File #1

Data Set Name: NIS_2004_10PCT_SAMPLE_A.ASC
Number of Records: 800,457
Record layout NIS 2004 Sample 1

10% Sample File #2

Data Set Name: NIS_2004_10PCT_SAMPLE_B.ASC
Number of Records: 800,457
Record layout NIS 2004 Sample 2

Severity Measures File

Data Set Name: NIS_2004_SEVERITY.ASC
Number of Records: 8,004,571
Record layout NIS 2004 Severity

Severity 10% Sample #1

Data Set Name: NIS_2004_10PCT_SEVERITY_A.ASC
Number of Records: 800,457
Record layout NIS 2004 Severity Sample 1

Severity 10% Sample #2

Data Set Name: NIS_2004_10PCT_SEVERITY_B.ASC
Number of Records: 800,457
Record layout NIS 2004 Severity Sample 2

Top

2003 NIS

Core File

Data Set Name: NIS_2003_CORE.ASC
Number of Records: 7,977,728
Record layout NIS 2003 Core

Hospital Weights File

Data Set Name: NIS_2003_HOSPITAL.ASC
Number of Records: 994
Record layout NIS 2003 Hospital

10% Sample File #1

Data Set Name: NIS_2003_10PCT_SAMPLE_A.ASC
Number of Records: 797,773
Record layout NIS 2003 Sample 1

10% Sample File #2

Data Set Name: NIS_2003_10PCT_SAMPLE_B.ASC
Number of Records: 797,773
Record layout NIS 2003 Sample 2

Severity Measures File

Data Set Name: NIS_2003_SEVERITY.ASC
Number of Records: 7,977,728
Record layout NIS 2003 Severity

Severity 10% Sample #1

Data Set Name: NIS_2003_10PCT_SEVERITY_A.ASC
Number of Records: 797,773
Record layout NIS 2003 Severity Sample 1

Severity 10% Sample #2

Data Set Name: NIS_2003_10PCT_SEVERITY_B.ASC
Number of Records: 797,773
Record layout NIS 2003 Severity Sample 2

Top

2002 NIS

Core File

Data Set Name: NIS_2002_CORE.ASC
Number of Records: 7,853,982
Record layout NIS 2002 Core

Hospital Weights File

Data Set Name: NIS_2002_HOSPITAL.ASC
Number of Records: 995
Record layout NIS 2002 Hospital

10% Sample File #1

Data Set Name: NIS_2002_10PCT_SAMPLE_A.ASC
Number of Records: 785,398
Record layout NIS 2002 Sample 1

10% Sample File #2

Data Set Name: NIS_2002_10PCT_SAMPLE_B.ASC
Number of Records: 785,398
Record layout NIS 2002 Sample 2

Severity Measures File

Data Set Name: NIS_2002_SEVERITY.ASC
Number of Records: 7,853,982
Record layout NIS 2002 Severity

Severity 10% Sample #1

Data Set Name: NIS_2002_10PCT_SEVERITY_A.ASC
Number of Records: 785,398
Record layout NIS 2002 Severity Sample 1

Severity 10% Sample #2

Data Set Name: NIS_2002_10PCT_SEVERITY_B.ASC
Number of Records: 785,398
Record layout NIS 2002 Severity Sample 2

Top

2001 NIS

Core File

Data Set Name: NIS_2001_CORE.ASC
Number of Records: 7,452,727
Record layout NIS 2001 Core

Hospital Weights File

Data Set Name: NIS_2001_HOSPITAL.ASC
Number of Records: 986
Record layout NIS 2001 Hospital

10% Sample File #1

Data Set Name: NIS_2001_10PCT_SAMPLE_A.ASC
Number of Records: 745,273
Record layout NIS 2001 Sample 1

10% Sample File #2

Data Set Name: NIS_2001_10PCT_SAMPLE_B.ASC
Number of Records: 745,273
Record layout NIS 2001 Sample 2

Top

2000 NIS

Core File

Data Set Name: NIS_2000_CORE.ASC
Number of Records: 7,450,992
Record layout NIS 2000 Core

Hospital Weights File

Data Set Name: NIS_2000_HOSPITAL.ASC
Number of Records: 994
Record layout NIS 2000 Hospital

10% Sample File #1

Data Set Name: NIS_2000_10PCT_SAMPLE_A.ASC
Number of Records: 745,099
Record layout NIS 2000 Sample 1

10% Sample File #2

Data Set Name: NIS_2000_10PCT_SAMPLE_B.ASC
Number of Records: 745,099
Record layout NIS 2000 Sample 2

Top

1999 NIS - Version 2

Core File

Data Set Name: NIS_1999_CORE.ASC
Number of Records: 7,198,929
Record layout NIS 1999 Core V2

Hospital Weights File

Data Set Name: NIS_1999_HOSPITAL.ASC
Number of Records: 984
Record layout NIS 1999 Hospital V2

10% Sample File #1

Data Set Name: NIS_1999_CORE10A.ASC
Number of Records: 719,893
Record layout NIS 1999 Sample 1 V2

10% Sample File #2

Data Set Name: NIS_1999_CORE10B.ASC
Number of Records: 719,893
Record layout NIS 1999 Sample 2 V2

Top

1999 NIS - Version 1

Core File

Data Set Name: NIS_1999_CORE.ASC
Number of Records: 7,198,929
Record layout NIS 1999 Core V1

Hospital Weights File

Data Set Name: NIS_1999_HOSPITAL.ASC
Number of Records: 984
Record layout NIS 1999 Hospital V1

10% Sample File #1

Data Set Name: NIS_1999_CORE10A.ASC
Number of Records: 719,893
Record layout NIS 1999 Sample 1 V1

10% Sample File #2

Data Set Name: NIS_1999_CORE10B.ASC
Number of Records: 719,893
Record layout NIS 1999 Sample 2 V1

Top

1998 NIS - Version 2

Core File

Data Set Name: NIS_1998_CORE.ASC
Number of Records: 6,827,350
Record layout NIS 1998 Core V2

Hospital Weights File

Data Set Name: NIS_1999_HOSPITAL.ASC
Number of Records: 984
Record layout NIS 1998 Hospital V2

10% Sample File #1

Data Set Name: NIS_1998_CORE10A.ASC
Number of Records: 682,735
Record layout NIS 1998 Sample 1 V2

10% Sample File #2

Data Set Name: NIS_1998_CORE10B.ASC
Number of Records: 682,735
Record layout NIS 1998 Sample 2 V2

Top

1998 NIS - Version 1

Core File

Data Set Name: NIS_1998_CORE.ASC
Number of Records: 6,827,350
Record layout NIS 1998 Core V1

Hospital Weights File

Data Set Name: NIS_1998_HOSPITAL.ASC
Number of Records: 984
Record layout NIS 1998 Hospital V1

10% Sample File #1

Data Set Name: NIS_1998_CORE10A.ASC
Number of Records: 682,735
Record layout NIS 1998 Sample 1 V1

10% Sample File #2

Data Set Name: NIS_1998_CORE10B.ASC
Number of Records: 682,735
Record layout NIS 1998 Sample 2 V1

Top

1997 NIS

Top

1996 NIS

Top

1995 NIS

Top

1994 NIS

Top

1993 NIS

Top

1992 - 1988 NIS

Top

User Support

NIS File Specifications