KIN 232 Module 3 Flashcards
Basic research
conducted to increase knowledge and fundamental understanding of the physical, chemical and functional mechanisms of life processes and disease.
Not directed to solving any particular problem in humans or animals
Applied research
involved the application of existing knowledge, much of which is obtained through basic research, to solve a practical problem
Clinical research
is patient or end user oriented research with human subjects. Patient-oriented research includes:
- Mechanisms of human disease
- Therapeutic interventions
- Clinical trials
- Development of new technologies
Translational research
part of a unidirectional continuum in which research findings are moved from the researcher’s bench to the patient’s bedside and to the community
Research design definitions: Descriptive
describes an outcome in a population
Characterizes who, where, or when in relation to the what (the outcome of interest)
Research design definitions: Analytical
Examines the relationship b/w intervention and outcome (independent/dependent variable, test hypothesis) the “how” and “why”
Research design definitions: Qualitative
- Subjective/interpretive observations
- Identifies themes in observations - forms narrative/story/essay
- Does not test a hypothesis, but may lead to hypothesis development
ex. surveys, questionnaires, intervies
Research design definitions: Quantitative
Objects/ measurable / units
Test hypothesis
ex. physiological variables, frequencies, instances, numerical simulations
Strengths of qualitative
Generates new ideas or hypothesis
Strengths of quantitative
Test hypotheses and examines cause and effect relationships
Quantitative research designs
- Observational
- Experimental
- Quasi experimental
Observational design
is non manipulated studies/research
Researchers do not attempt to influence/manipulate participants or the surroundings
Experimental design
Is a manipulated study
Participants are randomized to receive intervention or control
Quasi-experimental design
lacking 1 or more element of experiemental research
The utility of observational research
- Studying the otherwise un-studyable
- Priortizing external validity
- Generating research questions
Cross sectional observational research
- participants are observed at one point in time
- data/measurements are collected once
- Outcomes: single measure, prevalence of disease/events
advantages of observational cross sectional design
- less expensive
- less likely to drop out bc of short time
- controls for ‘period effects’
- data on ALL variables are collected at one time
disadvantages of observational cross sectional design
- Do not know whether exposure happen before or after outcome
- Associations identified between variables may be difficult to interpret
- snapshot timing not guaranteed to be reflective of ‘ real world’ setting
longitudinal observational research
- participants observed over time
- data/measurements are collected multiple times
- outcome: change over times provides indication of INCIDENCE of disease
advantages of longitudinal observational research
- you may observe patterns in the outcome over time
- establish an order of events
- reduces call bias of participants
- may provide insight into casual mechanisms
disadvantages of longitudinal observational research
- Time consuming and expensive
- Usually requires a large sample size
- Affected by ‘cohort effects’
- Cannot be used to suggest causation - only associations
- Despite temporal aspects - may not know if exposure precedes outcome
Prevalence
refers to the total number of individuals in a population who have a disease or health condition at a specific period of time, usually expressed as a percentage of the population
Who has the disease now?
Incidence
Incidence refers to the number of individuals who develop a specific diease or experience a specific heath-related event during a particular time period (such as a month or year)
Who will develop the disease over time?
What are the two observational study designs
case-control study: participants are selected based on an outcome of interest (e.g hypertension)
cohort study: participants selected based on a population of interest, a longitudinal study
Cohort
A collection or sampling of individuals who share common experiences and/or characteristics, such as age, sex, activity level, location, education
Types of cohort studies
Prospective: (forward in time)
- recruit participants + track them forward in time
- Outcome is evaluated in the future
Retrospective:
- Recruit participant and identify past/historical exposures
- Outcome is evaluated at time of recruitment (present day)
Advantages of cohort studies
Longitudinal : can determine temporal sequence of risk factors versus outcome
Best external validity: More likely to be representative of “real-life” scenario/environment
Representative : if the population is approrpiatley sampled, the risk estimates may be generalizable to the population
Multiple Exposures outcomes: Often multiple exposures and outcomes are evaluated wihtin one study
Disadvantages of cohort studies
- Large sample is required
- Expensive (participant compensation, researchers/staff)
- Attribution bias (over time people will drop out, tends to be people who are most sick)
- Measurement bias: if measurement methods cange over time, this may alter rate/risk estimates. Hard to measure certain variables consistently over time
- Poor internal validity
Population based recruitment strengths
cases are representative of population
results are generalizable to population
Population based population weaknesses
more difficult to recruit, how do we find the cases?
Hospital based recruitment strengths
easy to identify cases because they are already there
access to medical records
Hospital based recruitment weaknesses
Typically are more sick as they seek out more treatment
May be different in other ways compared to general population
Control group recruitment: How do we identify appropriate controls?
Want to match the controls as closely to the cases as possible
Challenges in case-control studies : Selection bias
selection bias occurs when the subjects studied are not representative of the target population about which conclusions are to be drawn
Challenges in case-control studies: Recall bias
a type of information bias common in case-control studies where the cases (or their families) are more likely to recall a prior exposure than the controls
Challenges in Case-control studies: Misclassification
Non- differential misclassification: cases and controls are misclassified equally , will make detection of a true effect less likely
Differential misclassification: only one group (cases or control) are misclassified, can alter the magnitude and/or direction of the effect
Case control studies
can be cross sectional, or longitudinal (always retrospective)
Absolute risk
the actual risk of some event happening given the current exposure. There is no comparison between groups.
Relative risk
Odds ratios
a measure of how strongly an event is associated with exposure.
The odds ratio is a ratio of two sets of odds: the odds of the event occuring in an exposed group versus the odds of the event occurring in a non-exposed group
The larger the odds ratio, the higher odds that the event will occur following exposure.
A ration equal to 1 means there’s no association between exposure and event ( a # greater than 1 will increase odds)
