Electronic Consumer Health Information: Where Has It Been? Where Is It Going?

1. Electronic Consumer Health Information:Where Has It Been?Where Is It Going? Jacquelyn Burkell Grant Campbell Faculty of Information and Media Studies University of Western Ontario OLA Super Conference 2004

2. Outline of Presentation: • Consumer Health Decisions • Screening Tests • The Sensitivity / Specificity Paradox • Allowing for the Decision • Electronic Consumer Health Information • Previous and Current Consumer Health Information • The Use of Metadata to Retrieve Documents • The Use of Metadata to Retrieve Information • Where We’re Headed

4. Sensitivity The percentage of real cases that test positive Sensitivity = True Positives True Positives + False Negatives

5. Specificity The percentage of negative cases that test negative Specificity = True Negatives True Negatives + False Positives

6. Base Rate • Incidence of the condition in the population being tested.

7. Example: The Maternal Serum Screening Test for Down’s Syndrome Base rate: 1% Sensitivity of test: 90% Specificity of test: 60%

8. Presence or Absence of Condition Test Result

9. Base Rate = 1% Incidence = 10 / 1000 Presence or Absence of Condition Test Result

10. Sensitivity = 90 % Presence or Absence of Condition Test Result

11. Specificity = 60% Presence or Absence of Condition Test Result

12. In any given 1,000 tests: 595 are likely to test negative, of which 1 will be a false negative. 405 are likely to test positive, of which 396 will be false positives. Presence or Absence of Condition Test Result

13. Positive Predictive Value: Negative Predictive Value: 9/405 = 2.2 % 594/595 = 99.8 % Predictive Values:

14. Positive Predictive Value: 0.25%

15. Positive Predictive Value: 0.48%

16. Positive Predictive Value: 2.2%

17. Positive Predictive Value: 6.7%

18. The State of Things In the Past • The “Vertical File” • Collections of articles, pamphlets and other ephemeral information sources, generally written for the lay person, containing practical advice on a variety of consumer health issues.

19. The State of Things In the Present • The “Web Resource Guide” • Subject-oriented electronic pathfinders, providing organized access to Web resources on consumer health issues • Example

20. Improvements: Stage One • Database Searching Assistance • The design of preformulated queries of medical databases based on anticipated decision-making needs • Example

21. Improvements: Stage Two • Metadata to Retrieve Web Documents • The use of a standard metadata element set to facilitate the retrieval of Web-based objects • The Dublin Core • Expansions

23. Improvements: Stage Three • Metadata to Retrieve Data Elements Within Documents • The use of metadata elements to mark parts of documents for subsequent retrieval and assembly into new documents • Automatic indexing or Manual indexing • Controlled vocabulary searching (MeSH)

24. MeSH: Psychological Phenomena --Mental Processes --Thinking --Decision Making MeSH: Investigative Techniques --Epidemiological Methods --Statistics --Sensitivity and Specificity MeSH: Diagnostic Imaging --Radiography --Mammography

25. What do we need to watch for in this brave new world? • Where can the information that people need be found? • Are the knowledge structures that we use sufficiently flexible for consumer health? • Is the information being presented in a way that promotes comprehension, and minimizes the risk of misinformation?

26. Please contact us for further information! Jacquelyn Burkell (jburkell@uwo.ca) Grant Campbell (gcampbel@uwo.ca) Faculty of Information and Media Studies University of Western Ontario London, Ontario N6A 5B7