Parts of a Research Article Flashcards
What are the parts of a published research article?
Introduction
Methods
Results
Discussion
Subcomponents of intro
Background
Purpose of study
Subcomponents of methods
Sample or study pop
How data was collected or datasets used
Variables and how they are measured
Statistical analysis
Subcomponents of results
Statistical description of the sample
Major results relating to the purpose of the study
Tables
Figures (graphs)
Subcomponents of the discussion
Fitting the results with previous research
Conclusions
Implications of the findings
How to read an introduction section
Look here for enough background to justify why this study should be done, followed by the purpose(s) of the study. The purpose of the study usually is found at the end of the introduction section. This section is not always labeled.
This section contains the context (background) and objectives of the study
Component of the background portion of the introduction section
Does this research need to be done?
Is there a hole in the literature that needs to be filled?
If so, the purpose of the study is to fill that hole
The purpose may be stated as a ________.
Hypothesis
What is a hypothesis?
A tentative suggestion that certain associations exist
On what is a hypothesis based?
Learned and scientific observation from which theories or predictions are made
How is a hypothesis used in epidemiology?
To evaluate suggestions about cause-effect relationships
What is another way in the which the purpose can be stated?
Research question
What is the format of a research question?
States the “a priori” hypothesis in the form of a question
What is part of the sample or study population subsection of the methods section?
Look here for a description of how the sample was recruited or selected, inclusion and exclusion criteria for being in the sample, and the source of the data.
What is part of the measurements subsection of the methods section?
A description of how the major variables of interest were defined and how these data were collected from the participants
What is part of the statistical analysis subsection of the methods section?
A description of how the data were analyzed.
Target population definition
The population about which information is desired
Source population definition
The population from which the sample was drawn
Actual sample or study pop definition
The group(s) that is/are actually surveyed and included in the analysis
What are the types of variables in epidemiology?
Exposure
Outcome
Covariate
Exposure definition
An independent variable that might cause or prevent a dz or death, a possible determinant
Risk factor definition
Any exposure that increases a person’s chance of developing a dz or of dying
Protective factor definition
Any exposure that decreases a person’s chance of developing a dz or of dying
Outcome definition
A dependent variable that is the effect or consequence of the risk and/or protective factor(s). In epi, this is usually the dz of interest or death
Covariate definition
Any other independent variable included in the analysis apart from the main exposure of interest and the outcome (Not always mentioned in the study purpose or objectives)
Definition of variable for analytic epidemiology
Any attribute that describes a person, place, or phenomenon, even or idea and that varies in value
Definition of association
A statistical relationship (such as correlation) between variables, usually between the exposure(s) and the outcome
What are the main independent variable(s) of interest?
Exposures, which pertain either to contact with a dz-causing factor or to the amount of the factor that impinges upon a group or individuals.
They are mentioned or implied in the purpose of the study
What are also mentioned or implied in the purpose of the study?
Outcomes
What are all different types of covariates?
Confounders, mediators, and moderators
Other terms for mediators
Intervening variable
Intermediate variable
Other terms for moderators
Effect modifier
Effect measure modification
Interaction
Confounder defintion
Any covariate (recognized or not) that distorts the association between the exposure and the outcome when it is not adjusted for
-When an observed association between an exposure and outcome is distorted because the exposure of interest is associated with some other variable that causes the outcome and is not in the causal pathway between the exposure and dz
What is the result of a confounding variable?
The odds ratio or relative risk is off, could be too high or too low
3 criteria of confounders
Be a risk factor (or protective factor) for the dz
Be associated with the exposure, independently of the dz
Not be an intermediate step in the causal pathway between the exposure and the dz (or not be a result of the exposure)
Definition of mediators, intermediate, or intervening variables
Any covariate that falls in the causal pathway. They are possible results of the exposure and causes of the outcome.
What criteria must be satisfied to be a mediator/intervening/intermediate variable?
Be an intermediate step in the causal pathway between exposure and dz
What occurs when a mediator or intermediate variable is adjusted for?
It will make the association between the exposure and the outcome appear weaker than it is
What will be placed in the results section?
Tables and figures, as will be a description of what is in the tables and what emerged statistically from the analyses. The major results connect back directly to the purposes of the study and flow solely from the data in this study
To what do results always refer?
Statistics, not to conclusions or inferences made from the statistics
Types of analysis
Univariate
Bivariate
Multivariate
Univariate analysis
This is sometimes an unadjusted, crude analysis betwen one exposure and the outcome. At other times if refers only to an analysis of one variable (either exposure, outcome, or covariate) in terms of distribution, mean, median, standard deviation, etc
Bivariate analysis
Here the two variables are referring to the exposure and the outcome. This is an unadjusted analysis, the same as a univariate analysis in some cases
Multivariate analysis
This is an adjusted analysis of several exposures (or an exposure and several covariates) all at once. It tells you the relationship between an exposure and an outcome, adjusted for all the other exposures or covariates entered into the model
What is part of the discussion and conclusion section?
Sometimes the results are restated at the start of the discussion, but not always
In this section, the significance of the results in the comparison to the findings of other studies are discussed
Limitations of the study are sometimes explicitly mentioned here, as are the implications for health promotion and policy (if any) and ideas for future research. The meaning of the results is here.
First key question to ask in terms of results
Could the association have been observed by chance?
First key question to ask in terms of results
Could the association have been observed by chance?
-Determined through the use of statistical tests (p values or confidence intervals)
Were the results statistically significant? What methods were used to measure the stability and precision of the association between exposure and outcome?
If no association was observed, was the sample size adequate to detect a meaningful effect? Is there any discussion of statistical power?
Second key question to ask in terms of the results
Were the results due to selection bias?
What bias might have been introduced into the findings by the approach to selection of participants?
-How were the study groups chosen and were selection criteria clearly defined?
-How were the comparison groups chosen?
-What were the response rates?
-Were all of the participants in the sample used in the analysis for this article? Why were some left out?
