A validation study is to be performed in a local hospital to check the accuracy of assessment of hospital-acquired infection (INF) following coronary bypass surgery (coronary-artery bypass graft, or CABG). In a given year the hospital performs 1100 CABG procedures. A Centers for Disease Control and Prevention (CDC) algorithm is currently used to categorize subjects as having INF. To validate this algorithm, all CDC^+ subjects (N = 100) and a random sample of CDC^- subjects (N = 1000) will be ascertained by an infectious-disease (ID) fellow and a detailed investigation will be performed, including a chart review and documentation of antibiotic use. Assume the ID-fellow's determination is correct. Suppose 100 CDC^+ subjects are ascertained, of whom the ID fellow confirms 80. Because there are a large number of CDC^- subjects (1000), only a sample of 100 is studied, of whom the ID fellow confirms 90.

What is the PV^+ of the CDC algorithm?

What is the PV^- of the CDC algorithm?

What is the sensitivity of the CDC algorithm?

What is the specificity of the CDC algorithm?