One of the main ways research is categorized is based on how data is sourced and collected. This distinction is particularly relevant for your work at ARPL, given that the plan primarily involves conducting systematic reviews (more on this later).
Primary Research
In simple terms, primary research involves collecting data directly from original sources, such as experiments, surveys, or interviews. As Furman University explains, “primary sources can be described as those sources that are closest to the origin of the information. They contain raw information and thus, must be interpreted by researchers.” This means that data is collected firsthand by the researcher. The main goal of primary research is to gather original, specific, and directly relevant information.
Secondary Research
In contrast, secondary research involves collecting and analyzing data from existing sources. In secondary research, your focus is on interpreting and synthesizing data that has already been collected by others. Scribbr puts it well: secondary research is what “provides second-hand information and commentary from other researchers.” Thus, when you analyze existing data collected by other scientists, you are conducting secondary research. This is the opposite of primary research, where you gather the data yourself.
It’s important to understand how to differentiate when a source can be considered primary or secondary, which is based on the topic and context in which it’s used. This distinction is particularly important because secondary sources are often closely related to primary sources and typically interpret or analyze them. Here’s an example to clarify the difference:
Let’s say you conduct an experiment to measure the effect of a new drug, collecting your own data. This would be considered a primary source, as you are gathering firsthand data through your research.
Now, let’s say you write a journal article that reviews several experiments to track the development of drugs for the same disease. In this case, the article would be a secondary source, because you are using data that was collected by others and has already been published.
In order to systematically differentiate between both types, you may firstly ask yourself who created the resource. If the resource was created by someone directly involved in the research (like the scientist conducting an experiment), then this type of research and data is primary. If the source was created by someone analyzing or interpreting research, then it is secondary.
You may also ask yourself: Does the source provide new, original information or summarize existing knowledge? If the source presents new data or firsthand, original findings, it is primary. If the source comments on, reviews, or synthesizes information already presented elsewhere, it is secondary.
For primary research, it primarily serves to make new discoveries and provide evidence for arguments and hypotheses. To ensure your research is original and reliable, it’s important to use primary sources. On the other hand, secondary research is foundational for gaining an overview of the topic you’re investigating. In pieces like systematic reviews and meta-analyses (which you’ll likely focus on more in ARPL), researchers often synthesize a large number of primary sources. This helps you build a strong background on the topic and may either support or contrast your arguments based on what other researchers have concluded, giving you a clearer understanding. Overall, most research combines both primary and secondary sources, as they complement each other. In many research papers, although the studies themselves are based on experiments and are primary research sources, they will still include a literature review section, or this review could even be part of the introduction. (We’ll explore what these sections are, and when, how, and why to write them, later.)
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Actually, there’s another type based on the source of data: tertiary sources. This type of resource is neither original (like primary) nor analytical (like secondary); instead, it compiles and organizes information.
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Tertiary sources usually provide a very broad idea or overview of your topic, but they don’t involve any analysis of the data. Examples include bibliographies, databases, encyclopedias, and so on. The main purpose of tertiary sources is to summarize or catalog information, which makes them helpful when gathering unanalysed background knowledge. (Encyclopedias are typically tertiary sources.)