Research Design and Approach Flashcards
What is gap analysis?
What do we know?
What do we need to know?
Why do we need to know?
What then is the gap?
What is the definition of study design?
A study design is a specific plan or protocol for conducting the study, which allows the researcher to translate the conceptual hypothesis into an operational one
Qualitative study method?
Qualitative means you collect words to describe the qualities of what you are studying: ideas, behavior, emotions, perceptions, opinions etc.
Useful to establish validity
Validity is the “truthfulness” of the information you gather, e.g., who will vote for the KPP?
Analyse by searching for themes
Usually smaller samples, not often representative.
Quantitative study design method?
Quantitative means you collect numbers
How many of one thing or another.
Useful to establish reliability
Reliability means representativeness.
Analyse through statistical procedures
Usually, large samples and representative samples
Hypothesis testing, often deductive
Prospective study?
looks forward
looks to the future
examines future events
follows a condition, concern or outcome into the future
Note: With a prospective study one starts with cohorts of well individuals, and we wait until events occurs.
Retrospective study?
“to look back”
looks back in time to study events that have already occurred
Note: Looking backward is often difficult because of recall bias, however, the case control studies are very inexpensive in comparison with prospective studies.
Name types of studies in order of increasing knowledge of diseases/exposure?
- descriptive study
- develop hypothesis - case control studies
- Investigate its relationship to outcomes - cohort studies
- Define its meaning with exposures - clinical trials
- test link experimentally
Cross sectional studies?
An “observational” design that surveys exposures and outcome status at a single point in time (a cross-section of the population)
- Cross section al studies are some of the first studies completed because of ease and low cost
Case contro studies?
one form of analytic study that provides information on the relationship between causal factors and injuries
- In a case-control study, subjects who have been injured are identified and their past exposure to suspected causal factors is compared with that of controls (persons who have not been injured).
Note: Many case-control studies ascertain exposure from personal recall, using either a self administered questionnaire or an interview. The validity of such information will depend in part on the subject matter. People may be able to remember recent events quite well. On the other hand, long term recall is generally less reliable.
Cohort design?
cohort studies follow a cohort of individuals who do not have disease, and then identified over time those individuals who have an outcome
How are prospective cohort studies done?
- The study begins by assessing baseline levels of the exposure and other variables
- Study subjects are then followed on a regular basis to identify the outcome
- The frequency of outcomes are tested between persons who had exposure to the possible risk factor at baseline and persons with no exposure.
How are retospective cohort studoes done?
This design is nearly identical to the prospective cohort study. The sequence of baseline exposure determination and longitudinal follow-up for outcomes is similar. The difference lies in the time in which the study begins. In this retrospective design, the researcher constructs the cohort study by looking back in time and placing data in the appropriate order and sequence. These studies are possible to do with large medical databases, such as the membership files of the Health Maintenance Organizations, or the medical files in the Scandinavian countries.
Strengths of cohort study?
- Exposure status determined before outcome detection
> so no temporal ambiguity
> so disease cannot influence the amount of error with which exposure status is measured - Subjects selected before outcome detection
> disease status does not influence of subjects - Can study several outcomes for each exposure
Limitations of cohort study?
- Expensive and time-consuming
- Inefficient for rare diseases or diseases with long latency
- Loss to follow-up
Experimental studies?
Concept: the effect of differences of an independent variable (or variables) on the behavior of the dependent variable are observed
An experimental study involves taking measurements of the system under study, manipulating the system, and then taking additional measurements using the same procedure to determine if the manipulation has modified the values of the measurements.
