2. Efficacy, Effectiveness and Efficiency
• Efficacy
– Randomized trial
• Effectiveness
– “real life”
– Do people come to be vaccinated?
• Efficiency
– Cost-benefit ratio
3. Measures of Outcome
• Measure must be quantifiable
• Measure must be relatively easy to define
• Measure must lend itself to standardization
• Population must be at risk for the condition
4. Comparing Etiology and Evaluation
Studies
• Studies of disease etiology
– Exposure of interest (e.g., smoking)
– Outcome of interest (e.g., lung cancer)
– Ask: Is there an association?
• Studies of health services evaluation
– “exposure” of interest is the health service
– Outcome of interest is reduction of adverse health
effects
– Ask: Is there an association?
5. Evaluation Using Group Data
• Advantages
– Issue of representativeness is minimized
– Quicker, data is ready, less expensive
• Disadvantages
– Incomplete data
– Not the data we really want
6. Evaluation Using Individual Data
• Like etiological studies, we compare two
populations, namely:
– One receiving care
– One not receiving care
• In order to do a good evaluation, we must feel
comfortable that:
– Characteristics of two groups are comparable
(demographics, medical conditions)
– Measurement methods are comparable
7. Study Designs
• Randomized designs
• Nonrandomized designs
– Before-after (historical controls)
– Simultaneous nonrandomized design (program –
no program)
– Comparison of utilizers and non-utilizers
– Comparison of eligibles and non-eligibles
– Combination designs
– Case-control studies
8. After reading the chapter…
• Can you define efficacy, effectiveness and
efficiency in the context of evaluating a health
service, for example vaccination?
• Can you compare and contrast epi studies of
disease etiology with epi studies evaluating
health services?
• Can you describe some possible study designs
that can be used to evaluate health services
using individual level data?
