Study Types Flashcards
What is a cross-sectional study?
investigates exposure characteristics and existing outcome in a group of subjects
Type of descriptive study that is designed to estimate the prevalence of disease or exposure. AKA prevalence study
Quetionnare, survey, point in time
(g)Fast, studies many aspects, cheap. (b) rare di., can’t determi. risk
How do cross-sectional studies enroll participants?
The sample is collected so that it is applicable to the independent population.
Tools must be scientifically valid and well-developed.
What is a prospective cohort study?
Follows outcome-free subjects into the future to determine their outcome.
How is a prospective cohort study enrolled?
Assess exposure and divide into exposure categories
Enroll after identifying exposure categories
Enroll subjects with specified exposure category.
What is a retrospective cohort study?
Involves the use of exposure information of subjects form the past and determines outcomes in the present.
How is a retrospective cohort study enrolled?
Assess exposure and divide into exposure categories
Enroll after identifying exposure categories
Enroll subjects with specified exposure category.
What is a case-control study?
Subjects have outcomes of interest (cases) and are compared to controls with no outcome.
- Outcome
- Exposure
How is a case-control study enrolled?
Cases are selected first, then controls are selected based on outcomes.
Exposures are investigated afterward.
Cases and controls are selected at the same time.
What is an ecological study?
Measurements like disease rates and information about exposures are made on a group of people.
compares health rates between different populations
Can generate questions and highlight issues
Compares different time periods and populations of people
How is an ecological study enrolled?
Populations are analyzed.
What is a case-series study?
Describes the characteristics of people who have the same disease or same exposure.
Can describe something unusual
Understands demographics
Clinical presentation
Shows prognosis
How are case-series enrolled?
N/A
What are randomized control studies?
Control group and experimental group undergo some sort of testing
Good causality
Randomization
-Not ethical, expensive, and many participants.
How are randomized control studies enrolled?
People are recruited
Identify the study design:
Researchers collect data on the average income and the prevalence of a specific health condition for different regions within a country. What study design is this, and what are its advantages and disadvantages?
ecological
Identify the study design:
A study involves the collection of detailed information on a small group of patients diagnosed with a rare disease to describe their clinical characteristics and outcomes. What study design is this, and what are its advantages and disadvantages?
Case-series
Identify the study design:
A new drug with in vitro activity against HIV is tested on a population of patients with Western-blot confirmed HIV infections. Out of the 200 individuals in the patient population, 100 are chosen at random to receive the drug. The drug, which is tasteless, is administered in a cup of orange juice; the other patients receive pure orange juice. Neither the nurses, doctors, nor patients know which patients receive the drug. At the end of the study period, the number of CD4+ T cells is determined for all of the subjects.
Experimental, randomized control trial
Identify the study design:
500 women aged 40-53 who present for routine check-ups are asked about their meat consumption. 20% of the women turn out to be vegetarian. During the ensuing 5 years, 5 vegetarians and 43 non-vegetarians developed colorectal cancer.
Prospective cohort
Identify the study design:
A group of patients with lung cancer is matched to a group of patients without lung cancer. Their smoking habits over the course of their lives are compared. On the basis of this information, researchers compute the odds of smoking among patients with lung cancer compared to the odds of smoking among those without lung cancer.
Case-control
Identify the study design:
Persons diagnosed with new-onset Lyme disease were asked how often they walk through woods, use insect repellant, wear short sleeves and pants, etc. Twice as many patients without Lyme disease from the same physician’s practice were asked about the same questions, and the responses of the two groups were compared.
Case-control
Identify the study design:
Researchers in India wanted to evaluate the prevalence of HIV and risk behaviors in male sex workers as well as the association between sociodemographic factors and HIV. The data were collected in June 2009 using interviewer-administered questionnaires (for sociodemographic and behavior data), clinical eval for sexually transmitted infections, and serological evaluation for STIs (like HIV).
Cross-sectional
Identify the study design:
The objective of a recently published study was to determine if fine particulate matter (a measure of air pollution) was associated with COVID-19 fatalities. Average fine particulate matter from 400 counties in Germany was obtained from the European Environment Agency. Daily numbers of confirmed COVID-19 deaths per 100,000 inhabitants were obtained from the Robert Koch Institute. The correlation between average fine particulate matter air pollution and COVID-19 deaths was estimated. Higher levels of fine particulate matter was positively correlated with COVID-19 deaths.
Ecological
Identify the study design of the following examples:
Researchers select a random sample of 500 college students from a specific university. This sample is representative of the entire student population in terms of age, gender, and academic majors. The researchers administered a questionnaire to the selected students at a single point in time, typically over the course of a few days or weeks.
Cross-sectional;
Simple random sampling
Identify the study design of the following examples:
A study compares two groups: one receiving a new drug, and the other receiving a placebo. What study design is this, and what are its advantages and disadvantages?
Randomized control study
