Reading the primary literature
Title: The title should convey the results and capture the reader’s attention.
Abstract: The abstract tells you:
1) What is the broad question that this work is related to? In other words, why is this work important?
2) What did the researchers do? What was the basic experimental design?
3) What are the main results?
4) What do the results mean in terms of the broad question?
Introduction: The introduction provides the contextual framework for the paper. What is the larger question that this work is related to? Who has done other similar work and what have they found? What are the outstanding questions in the field? How does this work answer some aspect of these questions?
Materials and Methods: The materials and methods section provides a step-by-step description of how the work was done with sufficient detail so that the experiment could be repeated by another investigator. All steps including the collection of materials, maintenance of living materials, experimental design, and data analysis should be included in this section.
Results: What are the results (NOT WHAT THEY MEAN!!). This is the section where tables and figures of resulted are presented. A description of the results is provided with no interpretation.
Discussion: This is the section where the researcher interprets the results and explains what s/he thinks they mean in relation to the questions presented in the introduction. Often this section, the author will compare and contrast the results with other research that had similar objectives. The author will likely provide more detailed descriptions of work that is of particular interest than was provided in the introduction.
Strategies for reading:
1. Get an overview of your subject from a textbook or the internet before plunging into a journal article.
2. Keep a dictionary (or the internet) handy.
3. Don’t read the article straight through. Start with abstract, then introduction, discussion, or the data depending on your level of comfort with the material.
4. Summarize information as you read (don’t write it down word for word), but only take notes if you have decided the source is useful.
Questions to ask yourself while reading:
1. What was/were the author’s question(s)?
2. What are the results of the study, and how convincing are they?
3. Were the assumptions made or methods used reasonable?
4. How did the results address the original question?
5. What are the larger implications of the study?
6. Does the literature cited section contain other articles I can use?
Common Statistics
Null hypothesis: Generally a hypothesis that there is:
No difference between different treatments
No effect of an independent variable
No relationship
Nothing special going on
P-value: The probability that the results deviate from the null hypothesis purely due to chance alone. A low P-value means that there is a strong chance that the null hypothesis is wrong, and that some variable does have a significant effect or that there is a significant difference between treatments. In general, science is not very willing to take chances. P-values < 0.05 are considered “significant.”
Regression: Author attempts to model the relationship between two or more continuous variables, usually using a mathematical equation (line).
Things to look for:
P-values: Measure whether the independent variable is making a significant contribution to the dependent variable’s behavior.
R2: How close the data points fit the model line (1 = perfect, 0 = not at all).
ANOVA (ANalysis Of VAriance): Author attempts to measure the amount of variability in a dependent variable that is due to different independent variables (typically categories of treatments).
Things to look for:
P-values: Measure whether the independent variable is responsible for a significant proportion of the variation in the dependent variable.
Types of articles
|
|
Research |
Review |
|
Generalizes what is known |
May |
Yes |
|
Describes methodology |
Yes |
No |
|
Gives in-depth statistics |
Yes |
No |
|
Narrow in focus |
Yes |
No |
|
Provides figures / tables |
Yes |
No |
|
Extensive reference list |
No |
Yes |