Skip directly to search Skip directly to A to Z list Skip directly to navigation Skip directly to site content Skip directly to page options
CDC Home

First State-Specific Healthcare-Associated Infections Summary Data Report CDC’s National Healthcare Safety Network (NHSN) January-June, 2009 Q&A

What is this report?

The First State-Specific Healthcare-Associated Infections Summary Data Report gives us a snapshot of where the country stands in our efforts to prevent central line-associated bloodstream infections (CLABSIs).  It provides both national and state-specific CLABSI data.   

Top of page

Why is CDC releasing this report now?

As the federal agency leading the charge to track and prevent healthcare-associated infections (HAIs), CDC has been working with healthcare facilities nationwide to collect and analyze HAI data on a national level for several years.  These data have led to numerous advancements in our understanding of HAI reporting, national HAI burden, and effectiveness of infection prevention strategies.  

Most recently, these data are being used for two important purposes.  From the national perspective, this is the first report to measure progress toward CLABSI prevention goals outlined in the U.S. Department of Health and Human Services Action Plan to Prevent Healthcare-Associated Infections.  On the state level, this report will serve as the baseline from which to assess impact of state-based HAI prevention programs, including those funded by the 2009 American Reinvestment and Recovery Act.

Top of page

How can this report be used?

Nationally, the report demonstrates progress toward HHS HAI Action Plan goals.  On the state level, it will serve as baseline data.  As additional reports are published, results will be compared against these data to determine the impact of prevention interventions. This information will help state and federal officials prioritize future surveillance, research, and prevention activities.

Top of page

What does this report tell us about how states are doing at preventing CLABSIs?

This report shows an 18 percent decrease in national CLABSI incidence. This encouraging finding reflects the work of facilities; local, state, and federal government; and cross-cutting partnership groups that have taken on CLABSI prevention efforts.  We hope that all states and healthcare facilities will be motivated to continue and strengthen efforts preventing CLABSIs.

Top of page

What is the next step?

The next step is for CDC to continue to strengthen its work with health departments in their efforts to begin or expand their own statewide HAI surveillance and prevention efforts.  CDC will also encourage additional facilities to enroll in NHSN and report progress on prevention efforts.

Top of page

What is a standardized infection ratio (SIR)?

The standardized infection ratio (SIR) is a summary measure used to track HAIs at a national, state, or local level over time.  The SIR adjusts for the fact that each healthcare facility treats different types of patients.  For example, the experience with HAIs at a hospital with a large burn unit (a location where patients are more at risk of acquiring infections) cannot be directly compared to a facility without a burn unit. 

The method of calculating an SIR is similar to the method used to calculate the Standardized Mortality Ratio (SMR), a summary statistic widely used in public health to analyze mortality data. In HAI data analysis, the SIR compares the actual number of HAIs in a facility or state with the baseline U.S. experience (i.e., standard population), adjusting for several risk factors that have been found to be most associated with differences in infection rates.

In other words, an SIR significantly greater than 1.0 indicates that more HAIs were observed than predicted, accounting for differences in the types of patients followed; conversely, an SIR of significantly less than 1.0 indicates that fewer HAIs were observed than predicted. 

Top of page

What does it mean that some states are validating their data?

Healthcare facilities and states are encouraged to validate, or double-check, their infection data.  In many cases, validating data involves completing an assessment to ensure that all of the required infections were captured in the system.  Currently, states that are validating are using different systems (e.g., some may evaluate one facility while others may look more broadly).  CDC is working with states to determine best practices and to develop standards for validation that can serve as a guide to assist states in their validation efforts. 

Top of page

Will a state that looks hard for infections have a higher SIR?

States that validate data and employ other advanced tools for detecting HAIs are likely to discover and report more infections.  For that reason, we have indicated in the report tables those states that are validating data so that these efforts are taken into consideration when evaluating the state’s performance.

Top of page

What does "predicted number of infections" mean?

CDC uses the HAI rates of a standard, or referent, population to help calculate predicted SIRs.  The predicted number is the HAI experience of the standard population, including data collected from all facilities—mandated and not—reporting CLABSIs to NHSN, during a certain time period (called a reference population).  For the purpose of this report, the reference group was risk adjusted and includes infection data reported to NHSN during January 2006–December 2008.     

Top of page

How does this report adjust for patient mix?

SIRs are adjusted by type of patient care location, hospital affiliation with a medical school, and bed size of the patient care location.  Other factors, such as facility bed size, were not associated with differences in rates and therefore were not included in SIR risk adjustment. 

Top of page

Why does this report only look at CLABSIs?

Most states with HAI mandates require CLABSI reporting.  However, the agency intends to update this report twice a year and will add other infection types and all states in future iterations.

Top of page

What are some reasons a state SIR is higher than 1.0?

While in many cases, high SIRs simply reflect a need for stronger CLABSI prevention efforts, several other factors such as validation of reported data may play a role.  This report establishes a baseline, but the real measure of success will come when future reports are released.  At that point, it will be appropriate to judge progress by comparing a state’s baseline to its most recent SIR. 

Top of page

What are some reasons a state SIR is lower than 1.0?

In many cases, low SIRs are a reflection of robust CLABSI prevention strategies.  These scenarios are exciting, and CDC is working with such facilities and states to learn and share best practices.  CDC is also considering the degree, if any, of under-reporting of HAIs in these data.  It is important to note that this report is not meant to compare states.  The real measure of progress will be comparing this baseline data to data in future reports.

It is important to note that an SIR of less than 1.0 is a positive finding, but it does not mean that the work is done.  Research has shown that rates of CLABSIs can be reduced further. 

Top of page

Why should states report HAIs?

CDC believes public reporting of HAIs is an important component of national HAI elimination and overall healthcare transparency efforts.  Research shows that when healthcare facilities are aware of their infection issues and implement concrete strategies to prevent them, rates of certain hospital infections can be decreased by more than 70 percent.  Infection data can give healthcare facilities, patients, and public health agencies the knowledge needed to design and implement prevention strategies that protect patients and save lives.

Top of page

Why is NHSN a good surveillance tool to measure HAIs?

The benefits of NHSN include standard methods and definitions, online training modules, user support, and facility comparison tools.  About half of all U.S. hospitals successfully report to NHSN, making it the largest HAI reporting system available.

Top of page

What is CDC doing about the states with high SIRs?

CDC is taking a proactive approach with all states.  The agency offers training and technical assistance to states to help them identify and assist healthcare facilities whose performance does not reflect effective prevention work.  Understanding SIRs will allow states to implement prevention efforts in areas where problems exist and to show prevention impact over time.

Top of page

What is the penalty for failure to report?

Currently, there is no uniform federal penalty for failure to report HAI data.  However, states with mandatory HAI reporting may have state-specific penalties for noncompliance with HAI reporting. 

Top of page

Does my state have a legislative mandate to report healthcare-associated infection data?

Currently, 28 states have implemented reporting laws, 21 of which utilize NHSN for their reporting requirements.  Please see the map at for a list of states with public reporting mandates.

Top of page

My facility wants to do more to track and reduce infection rates. How can I find out more information?

NHSN provides a secure way to track and analyze data on healthcare-associated infections, which can help improve infection rates.  For more information about NHSN and enrollment in NHSN, facilities should contact their local or state health department and visit

Top of page

Contact Us:
  • Centers for Disease Control and Prevention
    1600 Clifton Rd
    Atlanta, GA 30333
  • 800-CDC-INFO
    TTY: (888) 232-6348
  • Contact CDC–INFO The U.S. Government's Official Web PortalDepartment of Health and Human Services
Centers for Disease Control and Prevention   1600 Clifton Road Atlanta, GA 30329-4027, USA
800-CDC-INFO (800-232-4636) TTY: (888) 232-6348 - Contact CDC–INFO
A-Z Index
  1. A
  2. B
  3. C
  4. D
  5. E
  6. F
  7. G
  8. H
  9. I
  10. J
  11. K
  12. L
  13. M
  14. N
  15. O
  16. P
  17. Q
  18. R
  19. S
  20. T
  21. U
  22. V
  23. W
  24. X
  25. Y
  26. Z
  27. #