week 7 Flashcards
- What are observational designs
basically observing the effect of an exposure which can be characteristcs, preferences, practices lifestyles etc on a condition or disease without an intervention by researchers.
describe what descriptive research is as well as the level of control, the population, data collection used, types of results, statistical analysis
it describes the characteristcs of individuals/groups or it determines the frequency of a phenomon
level of control= none
population= represnative sample
data collection= tools, questionaires, clinical measurments etc
type of results= dempographics
statisical anaylsys” descriptive
describe correlational research as well as the level of control, the population, data collection used, types of results, statistical analysis
It explores or verifies the relationship between variables
level of control= none
population= representative sample
data collection =tools, questionaires, clinical measurments etc
types of results= assocition between variables
statisitical anaylsis= correlation or regression
what is the correlation coefficient r describing?
how well the point fits on a straight line, basicaly how strongly they are related with a positive or negative corelation, with 1 being a perfect correlation. When it is positive they are moving together and if negative they are in opositte directions
what is the regression coefficient beta ?
it is a number that tells you how much the depenant variable changes on average when another thing (the independent variable) changes by one unit
what are the 4 types of obersavtion research designs?
- cross-sectional
- retrospective
- prospective
- case-control
describe cross-sectional design
collects data at a specific time to provide information about a group in a population,
it can also be repeated cross-sectional which is basically to document trends, patterns by collecting the same data at multple points in time from different individuals for each data collection
what are the strengths and weakness of cross-sectional designs
strengths= less expesnive and faster since you do not need to follow up, can evaluate associations between variables and can be used as a basis for subsequent prospective or clinical studies
weakness= harder to know which variables would be cause and the effects, and is not suitable for studying rare diseases/conditons
prospective, retrospective and case-control design are all classes of temporal designs, describe them
- prospective= people are recruited before the condition/disease has develoiped to compare exposure factors throighout the study follow up
- retrospective: people are recruited after the condition or diseases has developed to compare exposure factors in the past
- case contol= is a retrospective evaultion used for people with a rare disease/conidtion compared to those without which would be the controls
what are the strengths and weaknesses of prospective designs
strengths= can measure the independent variables before the dependent even appears so closer to estabilising cause and effect, and therefore more complete and accurate measurments
weakness= expesnive and time consuming, often people dropout and associations may be affected by counfounding variables
- what are the strenth and weaknesses of retrospective design
strengths= less expesnive and faster since data has already been collected
weaknesses- no control over data co;;ected and some data can be missing
what are the strengths and weakness of case-control design
strengths= less expensive and faster, ideal for rare disease, smaller sample size needed
weaknesses= only one conditioned can be anyalzed, limited type of info collected, possible selection bias for choice of controls
there are two other types of observational designs that are less common what are they?
- ecological research: epidemiological study that compares populations instead of individuals to investigate assoications between enviromental factors and a diesease risk between popultations
- case study: a type of design used for rare cases that have limited available information
