HST.950/6.872 Problem Set 1

1. When we perform a test against certain kind of disease, the result can be divided into four categories:

True Positive (TP):	test result is positive and the disease is present
True Negative (TN):	test result is negative and the disease is not present
False Positive (FP):	test result is positive and the disease is not present
False Negative (FN):	test result is negative and the disease is present

Positive Predictive Value (PPV, or PV+) of such test can be estimated as TP/(TP+FP), and Negative Predictive Value (NPV, or PV-) can be estimated as TN/(TN+FN). Shortliffe gives a formula to calculate PV+ based on sensitivity, specificity, and prevalence. Please give a similar formula to calculate PV- using sensitivity, specificity, and prevalence, and show that when the sample size is large enough, the above estimation can be used to replace this formula. (Hint: you can also use TN, TP, FN, and FP to estimate sensitivity, specificity, and prevalence.)

2. Why do we need computer-based patient records (CPR)? What's the benefit over paper-based medical records? Please answer the question in LESS THAN 100 WORDS. You answer can include incomplete sentences, and bullets and/or tables are preferred format.

3. Describe an ideal CPR system in LESS THAN 300 WORDS based on the functional components and fundamental issues discussed in Shortliffe. Please highlight at least two properties of each functional component and the three most important aspects of each fundamental issue.

4. What kind of impediment would you expect to face when developing and using such a CPR?

5. (Shortliffe chapter 10, page 396, question 4) Describe the key philosophies underlying the design of central, modular, and distributed HCISs. What are at least two advantages and two disadvantages of each architecture?

6. Recent national attention has been drawn to the development of the "Electronic Health Record" (EHR). Some argue that it is essential to distinguish between an EHR meant to be shared among health care providers and a "Personal Health Record" (PHR) that is meant to inform patients and to allow them to keep track of their own diseases, treatments, immunizations, medications, etc. Muster some brief arguments for why these should be different, and some counter-argument for why they should be the same.