How to Read & Understand Scientific Papers
How to Read & Understand Scientific Papers on CBD
Reading and truly understanding a scientific paper is no fun - even for seasoned academics and researchers. In fact, there are entire first-year university and college courses about the subject!
But this is not just a problem in academia. Not understanding what a paper is really saying and getting the science wrong can actually be damaging. Taking data from animal studies and applying it directly to yourself and other humans can in a best-case scenario do nothing, worst-case scenario cause actual damage.
So, what if you’re just an average person? How do you read and understand scientific papers? When are researchers considered a scientific authority? And what constitutes enough proof?
Understand Scientific Papers - what to know before we start
The information we provide here is appropriate for people with no scientific background at all. Our intention is to help you get enough of an understanding of a paper to decide whether it is a reputable study.
We will also try to provide you with enough skill, that with patience and practice, will help you become familiar with the current research, using the “primary research literature” in the CBD and cannabis research field. This will not only help you understand the data and gauge its validity, but it will also help you draw accurate conclusions that will help you make educated decisions for yourself.
There are two primary types of research papers; a primary research article and a review article, both of which are peer-reviewed before publication. A primary research article refers to an article that reports on the details and results of a research study. A review article summarizes several primary research articles, summarizing the consensus, debates, and unanswered questions within a field. Although they are incredibly useful to get an overall view of what is going on, it is important to remember that research papers only provide a “snapshot” of the research available at that time. So, a research paper from the early 2000s will not be as useful as one that is a couple of years old.
Most primary research papers are divided into sections, the order of which will depend on which journal it’s published in. But generally speaking, you will find the following sections in most primary research papers:
- Abstract: A short and succinct summary of the paper
- Introduction: Provides all the relevant background information and a statement of the author's hypothesis
- Methods: Explains the methodology of the experiment, in other words, how the authors performed the experiment(s).
- Results: Contains the data collected during the experiment as well as the data analyzes and results thereof
- Discussion: The discussion section will explain the authors' interpretation of their data and how they connect it to other work
- Reference list / Cited literature: Provides the sources cited throughout the paper
- (Online) Supplementary Materials: Although not always included, this section contains important details of the research, but are published separately (usually online) instead of in the article itself
To help you gauge the level of “scientific authority” you can expect from an article, have a look at the authors and their institutional affiliations. Some institutions are more respected and rated higher than others. Some institutes may appear impartial and as if they do legitimate research but are actually agenda-driven.
The same goes for the journal the article is published in. Your best bet is to stick to papers from authors affiliated with universities and recognized research centers published in reputable journals listed on sites such as Web of Science.
Scientific papers can be complex, jarring and jargon filled that can make reading them somewhat confusing, and sometimes boring. So, while you read, it is important to take notes. Write down words you do not understand and look them up later - scientific terms have extremely precise meanings. And don’t forget to highlight the important information as this will help summarize the article.
How to Read & Understand Scientific Papers
So, let’s get to the important bit, how to read and understand a primary research paper. To help you with this process, we are going to use an article called Effect of Cannabidiol on Drop Seizures in the Lennox–Gastaut Syndrome published in The New England Journal of Medicine. We suggest you download and print it out by following the link. By using this to follow along with the distinct steps, it will give you a real-world and practical example that will help illustrate what we are talking about.
Step 1. Read the Introduction Section (Not the Abstract!) First
It is tempting to read the abstract first, and then just leave it there. After all, it is a dense and succinct summary of the paper and provides you with the highlights. And unfortunately, this is exactly what non-scientist tend to do when trying to understand CBD and cannabis research.
But this is a terrible practice. Abstracts (along with titles) are a great way for choosing papers, but not so good for trying to build a scientific argument. But, once you have a collection of relevant papers collected that are based on your interests, you need to read the introduction to understand the why, how and what of the experiment.
Step 2. Identify the Primary Research Question.For many non-scientists, identifying the primary research question can be a bit confusing. Many people think it is what the paper is about. But the primary research question, or BIG question, is actually more about the main issue that the entire field is trying to solve.
For instance, if you look at our paper on CBD for epilepsy, at first glance it would seem that the big question is the
“…efficacy and safety of cannabidiol added to a regimen of conventional anti-epileptic medication to treat drop seizures in patients with the Lennox–Gastaut syndrome…”.
But this is actually what the paper is about. The bigger question here is actually:
“IF CBD reduces drop seizures in patients with the Lennox–Gastaut syndrome”.
It is a subtle, but important difference you need to make when you are trying to understand the results of the experiment. It will also help you understand why this research is being done, how they are proposed is the best way of doing it, and if there is an agenda behind the research.
Step 3. Summarize the Introduction (Background) Section
A great way to do this is to answer the following questions:
- What work has been done before in this field to answer the research question (i.e., what do we know)?
- What are the limitations of that work (i.e., what do we not know yet)?
- What, according to the authors, needs to be done next (i.e., how will we find out)?
Being this concise about the information will help you really think about the content and context of the research. It will also help you explain it, which is the most important part of being able to understand it.
Step 4. Identify the Specific Research Questions
What exactly are the authors trying to answer with their research? These are the specific research questions and what the paper is about. Sometimes there may be multiple questions, sometimes there is just one. Sometimes they are obvious, and sometimes you have inferred them from the paper.
In our example, some specific research questions are:
- How effective and safe is CBD added to a regimen of conventional anti-epileptic medication to treat drop seizures?
- How many patients had at least a 50% reduction from baseline in drop-seizure frequency?
- How many patients had at least a 25%, 75% or 100% reduction from baseline in drop-seizure frequency?
- How many patients had a worsening or improvement in drop-seizure frequency?
Write them down. Again, it will help you understand what the researchers are investigating, why they are doing it as well as the integrity and objectivity of research is being done.
Step 5. Identify the approach
What are the authors going to do to answer these specific research questions?
In our paper this is:
“…a multicenter, randomized, double-blind, placebo-controlled trial to assess the efficacy and safety of two doses of cannabidiol, as compared with placebo, added to a regimen of conventional antiepileptic medication…”
Step 6. Read the Methods Section
A great way to understand the experiment and show exactly what the researchers did is to draw a diagram of each. Add in as much detail as you need to understand what they did.
The good thing is that you do not need to understand every single detail of the experiment. But you do need to understand it enough to explain the basics of it to someone else. If you cannot do that, you will not be able to understand the results.
Step 7. Read the Results Section.
Now we are getting to the nitty gritty of the paper. We suggest writing down the bullet points of each experiment to help summarize and clarify the results and what they mean. Figures and tables (and sometimes also the supplementary materials) are great visualizations of the data to help you understand them.
In our paper in figure 2 we can see that:
- The patients that received a placebo had a substantially smaller reduction in seizures than the two experimental groups for both the total number of seizures and drop seizures
- In the experimental groups, we can see that the patients who received 20 mg of CBD had a greater reduction in total seizures than the group of patients who received 10 mg of CBD
- In the experimental groups we can also see the patients who received 10 mg of CBD had a greater reduction in drop seizures than the group of patients who received 20 mg of CBD
It is tempting to draw conclusions from the results at this stage. But you should try not to decide what these results mean yet. Just write them down for now - we will come back to them later.
Other things you should pay attention to in the results section:
- The words “significant” or “non-significant”. These have precise statistical meanings as to the meaning of the results and the conclusions we can draw from them.
- The sample size. A study conducted on 10 people has a lot more statistical power (i.e., how confident we can be in our conclusions) than one in 10,000 people. For some research studies like clinical human trials, a sample size of 10 is sufficient. But generally speaking, the larger the better.
Step 8. Determine if the Results Answer the Specific Research Questions
Now you can start interpreting the results, think about what they mean and how relevant it is to the specific research questions. Do not skip ahead to the discussion section without having a really good think about this.
It is also important to remember that you might end up changing your mind once you have read the researchers discussion of their results. And that is perfectly ok. But starting to form your own interpretations and conclusions is an important step before you read those of others.
Step 9. Read the Discussion Section.
This where the researchers interpret their results and tell you what they think they mean. A good exercise for you is to see if you agree with them. Or do you have an alternative interpretation of the data?
Sometimes the authors also identify any weaknesses in their own study, questions they think are still unanswered, and what they propose the next steps are in the discussion section. However, if it’s not included, it does not necessarily mean it is a bad or biased study. There can be various reasons for this.
For instance, in our example, the researchers did not identify weaknesses in their own study. But, if you look at the Supplementary Materials, you will see that there are letters to the editor in which other researchers address certain shortcomings and issues. You will also find responses to these objections from the authors, which may explain why they did not consider these points as shortcomings and/or did not include it in their discussion.
Step 10. Lastly, Read the Abstract
Now you can decide if the authors did what they say they did. Does the abstract match with what the researchers said in the paper and does it fit with your interpretation of the results?
Once you’ve finished our suggested ten-step process for reading and understanding scientific papers, you might have a look at the reference section. You can use these to identify other interesting or important papers you might want to read as well.