Best Data Collection Methods for Quantitative Research

Posted on 15 June 2020 Catherine Chipeta

We explore quantitative data collection methods’ best use, and the pros and cons of each to help you decide which method to use for your next quantitative study.

There are many ways to categorise research methods, with most falling into the fields of either qualitative or quantitative.

Qualitative research uses non-measurable sources of data and relies mostly on observation techniques to gain insights. It is mostly used to answer questions beginning with “why?” and how?”. Examples of qualitative data collection methods include focus groups, observation, written records, and individual interviews.

Quantitative research presents data in a numerical format, enabling researchers to evaluate and understand this data through statistical analysis. It answers questions such as “who?”, “when?” “what?”, and “where?”. Common examples include interviews, surveys, and case studies/document review. Generally, quantitative data tells us what respondents’ choices are and qualitative tells us why they made those choices.

Once you have determined which type of research you wish to undertake, it is time to select a data collection method. Whilst quantitative and qualitative collection methods often overlap, this article focuses on quantitative data collection methods.

The Nature of Quantitative Observation

As quantitative observation uses numerical measurement, its results are more accurate than qualitative observation methods, which cannot be measured.

To ensure accuracy and consistency, an appropriate sample size needs to be determined for quantitative research. A sample should include enough respondents to make general observations that are most reflective of the whole population.

The more credible the sample size, the more meaningful the insights that the market researcher can draw during the analysis process.


Collecting data with surveys

Quantitative surveys are a data collection tool used to gather close-ended responses from individuals and groups. Question types primarily include categorical (e.g. “yes/no”) and interval/ratio questions (e.g. rating-scale, Likert-scale). They are used to gather information such based upon the behaviours, characteristics, or opinions, and demographic information such as gender, income, occupation.

Surveys are traditionally completed on pen-and-paper but these days are commonly found online, which is a more convenient method.

When to use

Surveys are an ideal choice when you want simple, quick feedback which easily translates into statistics for analysis. For example, “60% of respondents think price is the most important factor when making buying decisions”.

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  • Speedy collection: User-friendly, optimal length surveys are quick to complete and online responses are available instantly.
  • Wide reach: Online survey invites can be sent out to hundreds of potential respondents at a time.
  • Targeted respondents: Using online panels allows you to target the right respondents for your study based on demographics and other profiling information.


  • Less detail: Surveys often collect less detailed responses than other forms of collection due to the limited options available for respondents to choose.
  • Design reliant: If survey design is not effective, the quality of responses will be diminished.
  • Potential bias: If respondents feel compelled to answer a question in a particular way due to social or other reasons, this lowers the accuracy of results.


Quantitative interviews

Quantitative interviews are like surveys in that they use a question-and-answer format. The major difference between the two methods is the recording process.

In interviews, respondents are read each question and answer option to them by an interviewer who records responses, whereas in surveys, the respondent reads each question and answers themselves, recording their own response.

For quantitative interviews to be effective, each question and answer must be asked the same way to each respondent, with little to no input from the interviewer.

When to use

Quantitative interviews work well when the market researcher is conducting fieldwork to scope potential respondents. For example, approaching buyers of a certain product at a supermarket.


  • Higher responsiveness: Potential respondents are more likely to say ‘yes’ to a market researcher in-person than in other ways, e.g. a phone call.
  • Clearer understanding: Interviews allow respondents to seek classification from the interviewer if they are confused by a question.
  • Less downtime: The market researcher can collect data as soon as the interview is conducted, rather than wait to hear back from the respondent first.


  • Interviewer effect: Having an interviewer present questions to the respondent poses the risk of influencing the way in which the respondent answers.
  • Time consuming: Interviews usually take longer to complete than other methods, such as surveys.
  • Less control: Interviews present more variables, such as tone and pace, which could affect data quality.

Secondary Data Collection Methods

Secondary data for quantitative research

Published case studies and online sources are forms of secondary data, that is, data which has already been prepared and compiled for analysis.

Case studies are descriptive or explanatory publications which detail specific individuals, groups, or events. Whilst case studies are conducted using qualitative methods such as direct observation and unstructured interviewing, researchers can gather statistical data published in these sources to gain quantitative insights.

Other forms of secondary data include journals, books, magazines, and government publications.

When to use

Secondary data collection methods are most appropriately used when the market researcher is exploring a topic which already has extensive information and data available and is looking for supplementary insights for guidance.

For example, a study on caffeine consumption habits could draw statistics from existing medical case studies.


  • Easier collection: As secondary data is readily available, it is relatively easy to collect for further analysis.
  • More credibility: If collected from reputable sources, secondary data can be trusted as accurate and of quality.
  • Less expensive: Collecting secondary data often costs a lot less than if the same data were collected primarily.


  • Differing context: Secondary data collected will not necessarily align with the market researcher’s research questions or objectives.
  • Limited availability: The amount and detail of secondary data available for a particular research topic is varied and not dependable.
  • Less control: As secondary data is originally collected externally, there is no control over the quality of available data on a topic.


Quantitative research produces the most accurate and meaningful insights for analysis.

Surveys are a common form of quantitative data collection and can be created and completed online, making them a convenient and accessible choice. However, they must be well-designed and executed to ensure accurate results.

Interviews are an ideal choice for in-person data collection and can improve respondents’ understanding of questions. Time and potential interview bias are drawbacks to this method.

Collecting secondary data is a relatively quick and inexpensive way of gathering supplementary insights for research but there is limited control over context, availability, and quality of the data.

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