Designing Research » Quantitative vs Qualitative Methods

What you'll learn this session

Study time: 30 minutes

The difference between quantitative and qualitative research methods
Strengths and limitations of each approach
How to select appropriate methods for different research questions
Real-world applications of both methods in psychology
How to evaluate research based on methodology

Quantitative vs Qualitative Methods in Psychology

When psychologists conduct research, they need to decide which type of data will best answer their research question. This choice leads them to either quantitative or qualitative methods - two fundamentally different approaches to gathering and analysing information about human behaviour and experience.

Key Definitions:

Quantitative research: Collects numerical data that can be statistically analysed, focusing on measuring and counting.
Qualitative research: Collects non-numerical data such as words, observations and experiences, focusing on meaning and understanding.
Data: Information collected during research that can be analysed to draw conclusions.
Variables: Factors or characteristics that can be measured and that may change or vary across participants or conditions.

📊 Quantitative Methods

Quantitative methods involve collecting data that can be expressed numerically and analysed using statistics. These methods aim to measure, count and establish cause-and-effect relationships.

Examples include:

Experiments
Surveys with closed questions
Structured observations
Psychometric tests

💬 Qualitative Methods

Qualitative methods involve collecting rich, detailed data about people's experiences, thoughts and feelings. These methods aim to understand meaning and explore topics in depth.

Examples include:

Interviews
Focus groups
Case studies
Unstructured observations

Comparing the Approaches

🔬 Research Questions

Quantitative: "How many...?" "What is the relationship between...?" "Does X cause Y?"

Qualitative: "Why...?" "How...?" "What does it mean to...?"

👥 Sample Size

Quantitative: Usually large samples to ensure statistical significance and generalisability

Qualitative: Often smaller samples studied in greater depth

📋 Data Collection

Quantitative: Structured, standardised, often uses measurement tools

Qualitative: Less structured, adaptable, focuses on natural settings

Strengths and Limitations

Quantitative Methods: Strengths

Objectivity: Less influenced by researcher bias
Reliability: Easier to replicate and check findings
Generalisability: Findings can often be applied to wider populations
Statistical analysis: Allows for precise comparisons and predictions
Efficiency: Can collect data from many participants relatively quickly

Quantitative Methods: Limitations

Lacks depth: May miss important details about why people behave as they do
Artificial settings: Lab experiments may not reflect real-world behaviour
Reductionist: Complex human experiences reduced to numbers
Inflexible: Difficult to change course once data collection has begun
Researcher assumptions: Questions and measures reflect researcher's preconceptions

Qualitative Methods: Strengths

Rich data: Provides detailed insights into experiences and feelings
Flexibility: Can adapt as new information emerges
Holistic: Examines the whole person in context
Participant voice: Allows participants to express themselves in their own words
Exploratory: Ideal for investigating new or complex topics

Qualitative Methods: Limitations

Subjectivity: More vulnerable to researcher bias
Limited generalisability: Findings may not apply to wider populations
Time-consuming: Data collection and analysis often takes longer
Reliability concerns: Harder to replicate findings
Interpretation issues: Different researchers might interpret the same data differently

Case Study Focus: Mixed Methods Research

Many psychologists now use mixed methods approaches, combining quantitative and qualitative techniques to get the best of both worlds. For example, a study on teenage anxiety might use questionnaires to measure anxiety levels across a large sample (quantitative) and then interview a smaller number of highly anxious teens to understand their experiences in depth (qualitative).

The 2018 study by Smith et al. on school-based mindfulness programs used this approach. They measured stress levels before and after the program using standardised scales (quantitative) and conducted focus groups to understand how students experienced the intervention (qualitative). This gave both statistical evidence of effectiveness and insights into how and why the program worked.

Choosing the Right Method

When designing research, psychologists consider several factors to decide whether quantitative or qualitative methods (or both) are most appropriate:

💡 Research Question

The most important factor is what you're trying to find out:

If you want to test a hypothesis, measure something precisely, or establish cause and effect → Quantitative
If you want to explore experiences, understand meanings, or develop new theories → Qualitative

🛠 Practical Considerations

Other factors that influence method choice:

Available resources (time, money, equipment)
Access to participants
Researcher skills and experience
Ethical considerations
What previous research has done

Real-World Applications

Quantitative Methods in Action

The famous Milgram obedience studies used quantitative methods to measure how many participants would obey an authority figure's instructions to deliver electric shocks to another person. By counting the percentage of people who continued to the maximum voltage level (65%), Milgram could make statistical claims about human obedience to authority.

Modern applications include:

Clinical trials testing the effectiveness of new therapies
Surveys measuring attitudes toward mental health across different age groups
Experiments examining the impact of sleep deprivation on cognitive performance

Qualitative Methods in Action

Zimbardo's Stanford Prison Experiment, while controversial, used qualitative observations to document how quickly ordinary students adopted brutal guard behaviours or became passive prisoners. The rich observational data revealed psychological processes that numbers alone couldn't capture.

Modern applications include:

Interview studies exploring how people cope with grief
Observational research on classroom dynamics
Case studies of individuals with rare psychological conditions

Exam Tip: Evaluation Points

In your exam, you might be asked to evaluate research methods. Remember these key points:

For quantitative methods: Highlight objectivity, reliability and generalisability, but note potential issues with ecological validity and depth of understanding.
For qualitative methods: Emphasise rich data and flexibility, but acknowledge concerns about subjectivity and limited generalisability.
Always link your evaluation to the specific research question - what matters is whether the method is appropriate for what the researcher wants to find out.

Summary: Making Your Choice

When deciding between quantitative and qualitative methods, there's no universally "better" approach - it depends entirely on what you want to know. Think of them as different tools in your research toolkit:

Quantitative methods are like a ruler - precise for measuring things but can't tell you much about experiences or meanings.
Qualitative methods are like a magnifying glass - excellent for examining details and nuances but not designed for broad measurements across large groups.

The best psychologists understand the value of both approaches and know when to use each one - or how to combine them effectively in mixed methods research.

🧠 Test Your Knowledge!