Case Studies and Case Series Research

Question 1

Case study research

Answer 1

One person, one case.
Cannot determine cause and effect.
Usually qualitative. 
Allows comparison of effects of different conditions on one person. 
Much more detailed than RCT.

Question 2

General protocols of a case study/series

Answer 2

1. Define the objectives of the case study
2. Define the case - the patient, their condition and all known factors related to it.
3. Define the source of the case. (Did you get participant from the hospital, another clinic).
4. Define the units of measurement of the objectives. (Outcome measures)

Question 3

Time frame for a case study

Answer 3

1. Control period, assessments at the beginning and end.
2. Intervention period, assessment at the end.
3. Follow-up period, assessments in the middle and end. (Washout period from beginning to, depending on the patient.

Question 4

Control period

Answer 4

1st assessment will determine baseline parameters of participant.
2nd assessment determines if any events or factors are affecting the participant in a negative or positive way, concerning the parameters.

Question 5

Washout period

Answer 5

Effects will washout over time.

Difficult to determine in non drug trials.

Question 6

Follow-up period

Answer 6

Assessing the extent of the effects of the intervention and for how long the effects of the intervention is maintained.

Question 7

Outcome Measures

Answer 7

Is patient getting better, same or worse. 
Measurable parameters.
Several parameters can be tracked.
Include parameters of: 
- Physiological function
- Activity
- Participation
- Quality of life

Question 8

Case Series

Answer 8

More than one participant.
Not comparing participants.
The association between the intervention and the observed outcome cannot be tested statically, because confounders are not controlled.

Question 9

Confounding Factors

Answer 9

Anything that can confuse the results of the research.

Question 10

Advantages of a Case Study

Answer 10

• Useful for studying a rare phenomena.
• Real life situations, no control for confounding factors.
• Flexibility of the time frame for studies.
• Outcomes can be used to generate hypotheses.

Question 11

Disadvantages of a Case Study

Answer 11

• Not generalizable (lacks external validity).
• Time consuming.
• Difficult to summarize as many factors are involved in real life situations.
• Descriptive only. Does not determine relationships between variables.

Question 12

Conditions necessary for Confounding to occur.

Answer 12

1. The confounding factor must have the same effect on the dependent variable as does the independent variable.
2. The confounding factor must not be an intermediate step in the pathway of the relationship between the independent variable and the dependent variable.
3. The confounding factor must not be an effect of the independent variable.

Question 13

Controlling effects of Confounding Factors

Answer 13

Not for case studies (series)

• Randomization: Confounding factor evenly distributed.
• Population matching/restriction: Homogeneous population. Making sure people in both groups are the same.
• Stratification of estimates of effects: Shows how much the confounding factors affects the dependent variable.