There are two sources of data: primary and secondary. Most research projects use both.
What is primary and secondary research?
Primary research means collecting new data yourself. Common research methods include surveys, interviews, experiments, case studies, and observations. It produces new findings that are original to your project.
Secondary research uses data that others have already collected. Sources include books, journal articles, reports, and statistics. The goal is to use existing data to answer new questions.
Some projects rely entirely on secondary research. However, even projects that collect primary data will use existing literature to support and inform their work.
Where your data comes from is a separate decision from your data type. Table 1 below gives some examples of how each of these dimensions can combine.
Table 1. Data type matrix.
|
Primary data (data you collect yourself) |
Secondary data (data others have collected) |
|
|---|---|---|
|
Quantitative (numeric data) |
A survey you design and run | Government statistics or published datasets |
|
Qualitative (non-numeric data) |
Interviews or observations you conduct | Published case studies or interview transcripts |
Choosing your approach
The right approach depends on your research question and your resources.
Ask yourself…
- Does the data I need already exist, or do I need to collect it?
- Do I have access to the participants, documents, or data sources I need?
- Do I have enough time to collect primary data?
If the data you need already exists and is reliable, secondary research may be sufficient. If it does not, primary research is necessary.
Ethics in primary research
Primary research requires ethical approval, and you must also get informed consent. This includes keeping participants’ identity and responses confidential and ensuring they can stop taking part at any time.
Complete an ethics form and get University approval before you collect any data. Your research supervisor will help you through this process.
Read more about research ethics.
Evaluating secondary sources
Sources vary in quality. Table 2 below gives a guide to source quality.
Table 2. Source quality guide.
| Source type | Examples | Value | Notes |
|---|---|---|---|
| Academic journals | Peer-reviewed articles | High | Checked by experts; this is where new research is published |
| Academic books | Textbooks, edited collections | High | Expert overviews of academic subjects |
| Official statistics | Office for National Statistics | Good | Reliable but descriptive, not critical |
| Grey literature – material produced outside academic publishing | Government reports; non-governmental organisation (NGO) reports; company reports | Fair | Useful but may reflect the organisation’s interests or political position |
| General websites | Blogs, wikis, news sites | Low | Use with caution; no guarantee of accuracy or expertise |
| Essay websites | N/A | Avoid | No guarantee of accuracy or expertise |
| AI-generated content | ChatGPT, Copilot, Claude and similar tools | Avoid as a source | AI tools can support your studies in other ways; our guidance on using AI at university explains how |
Page last edited: 4 August 2026
Next review due: 4 August 2029