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Screening Program Data
Interpretation and Use of Data
The purpose of the NBCCEDP Screening Program Summaries report is to disseminate results of the national program to the public and recognize services provided and cancers detected through individual state, territorial, and tribal programs. These data represent only clinical services provided through direct NBCCEDP federal funding.
These data include screening and diagnostic services and clinical outcomes for the most recent 5-year period for which data are available. The 5-year timeframe provides a current snapshot of the program and assures a quantity needed to minimize data suppression. Data are suppressed for programs with fewer than 200 screens, cell sizes less than 16, and rates and percentages that do not meet a test of relative standard error less than 30%, a measure of the estimate's reliability.
By program definition, "women screened" are those receiving a program-funded screening procedure, including mammography, clinical breast exam, or Pap test. Although women screened represent the core of the program, "women served" include additional women receiving diagnostic services through the program following an abnormal screening test funded through another source.
The number of "unduplicated" women do not reflect the quantity of screening services provided to these women over the 5-year period. The program places a high priority on rescreening women at recommended intervals, and invests significant effort and resources to recall women to return for rescreening. About half of all screens provided each year are to women previously screened through the program.
Rates and percentages of screening and diagnostic outcomes are presented in crude form and age-adjusted by the direct method to the population of NBCCEDP participants screened in calendar year 2000. As incidence of cancer is influenced by age, age-adjusting to a standard population is used to minimize variation in rates attributed to differences in age distribution across time periods or geographic areas.
As an unintended result, age-adjusting can distort rates when an age group is characterized by other factors in addition to risk of cancer. As an example, some programs recruit only older women into the program for screening, but occasionally enroll younger women presenting with symptoms or referred to the program with an abnormal screen provided through another source. In this case, the younger women are under-represented in the population but have unusually high rates of cancer as they entered the program as high-risk patients. This is a factor of recruitment and enrollment practices which vary across programs, particularly for cervical cancer screening.
In addition, rates are impacted by the occurrence of pre-existing cancers found in women receiving their first program screen. Cancers are detected more frequently in women newly enrolled, particularly when women most at risk are recruited. To control for this potential bias, rates are often estimated separately for women receiving routine screening from those women first entering the program. For these and additional descriptive results from the NBCCEDP, see the 1991–2002 National Report (PDF-1.3MB).
It is important to recognize that these data represent the NBCCEDP screened population and are not an estimate of the general population. For general population statistics on breast and cervical cancer, see State Cancer Burden Data.
Variation Across Programs
National aggregate data are typically used to report results from the program and as a standard of comparison for individual grantee screening programs. Comparing performance data across grantee programs is not advised due to extensive variation across programs.
Although individual programs operate within a national program framework of legislation, policy, and oversight, no two programs are alike. Programs vary in the amount of funding and other resources available, program infrastructure for management and service delivery, population demographics, and other unique characteristics of the jurisdiction such as cultural and geographical barriers to screening.
Provision of services is tied to many factors, for example:
While program data are useful in quantifying service delivery and outcomes, these data alone do not reflect the full benefit of the program. Additional benefits result from other activities of the program related to public and professional education, development of partnerships and infrastructure within communities, and improvements in the quality of clinical services. These activities extend the value of the program beyond support of direct clinical services to eligible women.
Please note: Some of these publications are available for download only as *.pdf files. These files require Adobe Acrobat Reader in order to be viewed. Please review the information on downloading and using Acrobat Reader software.
Page last reviewed: October 12, 2007
Page last updated: October 12, 2007
Content source: Division of Cancer Prevention and Control, National Center for Chronic Disease Prevention and Health Promotion