REFERENCES
Agency for Healthcare Research and Quality. (2016). Screening for breast cancer with
digital tomosynthesis. Retrieved from http://www.uspreventiveservicestaskforce.org/Home
/GetFile/1/16477/dbt-screen-tomo-finalevidrev/pdf
AIDS.gov. (n.d.). A timeline of AIDS. Retrieved from https://www.aids.gov/hiv-aids-basics
/hiv-aids-101/aids-timeline/
Centers for Disease Control and Prevention. (n.d.). Steps of an outbreak investigation.
Retrieved from https://www.cdc.gov/foodsafety/outbreaks/pdfs/steps-in-oubreak
-investigation-508c.pdfApply What You Have Learned
As committee members have been reviewing the evidence, they are finding that some studies
use epidemiological approaches to examine data. For example, Chhapola and Brar (2015)
examined the impact of their handwashing intervention on times when hand hygiene is
indicated. Look at Table 1, on page 489, to see the relative risk (RR) values for each of the five
observations. When the intervention is used, at which observation are HCWs 1.25 times more
likely to comply with hand hygiene guidelines?» Epidemiologists calculate an OR for a case-control study design. They calculate an RR when
conducting a cohort study.
» Screenings are tests to identify symptoms of disease and are not diagnostic. Screenings involve
testing people without known disease to determine whether they have a disease. They are
used to reduce morbidity and mortality in a population.
» Sensitivity, specificity, and positive predictive value are measures used to describe the validity
of a screening test.
» When the sensitivity of a test increases, the specificity of the test will decrease. When the
sensitivity decreases, specificity will be increased.
» Epidemiologic designs can be used to investigate patterns of disease and evaluate cost-benefit
of screening initiatives.
» False-positive and false-negative results from screenings can have ethical implications related
to psychological and financial costs.218 CHAPTER 8 Epidemiologic Designs: Using Data to Understand Populations