Learning Objectives
Evaluate strengths and weaknesses of research by linking sampling, methods, question design, recording, bias, ethics and context to the purpose and reliability of the investigation.
Purpose Of Question 2(a)
The first part of Question 2 asks you to evaluate research or evidence described in a source. Evaluation means explaining how particular features strengthen or weaken the research in relation to its purpose.
Do not merely identify features. “The sample is small” is an evaluative point, but it needs development: explain why the small sample limits representativeness or confidence in the conclusion.
Start With The Research Purpose
Before evaluating, identify what the researcher was trying to discover. A method can be suitable for one purpose and unsuitable for another. An interview may provide deep personal experience but cannot by itself show how common an attitude is across a large population.
Evaluation Sentence
Feature + effect on the research + link to purpose or conclusion.
Original Example
“The researcher interviewed only members of one sports club. This is a narrow sample, so their positive views may not represent young people who do not already participate in sport. The evidence is therefore weak for a general claim about all young people.”
Sample Size
A larger sample can increase confidence that results are not based on a few unusual individuals. However, size alone is not enough. A very large biased sample can still be unrepresentative.
Ask
How many people or cases were included, and is that number suitable for the claim being made?
Representativeness
A representative sample reflects important characteristics of the target population. Consider age, gender, location, income, occupation or other relevant variables. A sample taken from only one school, neighbourhood or online group may not represent a wider population.
Avoid automatically claiming that every local study is weak. If the purpose is to investigate that particular local group, a local sample may be appropriate.
Sampling Method
Random or carefully stratified sampling may reduce selection bias. Convenience sampling is easier but may overrepresent people who are nearby, available or willing to respond. Voluntary online polls often attract people with strong opinions.
Original Example
A public transport company posts a survey only on its mobile app. This excludes non-users and people without smartphones, so the results may overrepresent regular digital customers.
Research Method
Different methods produce different kinds of evidence. Interviews provide depth but can be time consuming and influenced by the interviewer. Questionnaires can reach many people but may produce brief or misunderstood answers. Observation records behaviour but may not reveal motives. Experiments can test causation but may be artificial or ethically difficult.
Evaluation should match the method to the research question rather than declaring one method always superior.
Question Design
Leading, vague, double-barrelled or emotionally loaded questions can distort responses.
Leading Question
“Do you agree that the dangerous new road should be cancelled?” The wording encourages agreement by describing the road as dangerous.
Double-Barrelled Question
“Are buses cheap and reliable?” A respondent may think they are cheap but unreliable and cannot answer accurately with one option.
Conditions Of Data Collection
Noise, lack of privacy, time pressure, the presence of authority figures and poor recording can reduce accuracy. Participants may give socially acceptable answers rather than honest ones when confidentiality is weak.
Explain the likely effect. For example, if an employer is present, workers may avoid criticism, making results overly positive.
Researcher And Participant Bias
Researchers may select evidence that supports their expectations. Participants may exaggerate, forget details or have a vested interest. This does not mean their evidence has no value; it means it should be checked against other sources.
Triangulation
Triangulation means comparing evidence from different methods, groups or sources. Agreement across independent evidence can strengthen confidence in a finding.
Accuracy And Recording
Audio recordings, written records, clear measurement procedures and transparent data tables can improve accuracy. Memory-based notes may omit details. Unclear units or inconsistent procedures make comparison difficult.
A claim that a source is “accurate” needs evidence. Explain what procedure makes accurate recording more or less likely.
Primary And Secondary Evidence
Primary research is collected directly for the investigation, such as interviews or observations. Secondary research uses existing material, such as published reports and datasets. Primary evidence can be closely matched to the question, while secondary evidence can provide wider comparison or expert research.
A strong project often combines both, but the best combination depends on the purpose.
Date And Context
Recent evidence may be important for rapidly changing issues such as technology use or prices. Older evidence may still be useful for long-term trends. Consider whether the place and circumstances of the evidence match the claim.
Context Limitation
A study of remote learning during an emergency school closure may not represent ordinary online education because the conditions were unusual.
Ethics
Ethical research gains informed consent, protects privacy, avoids unnecessary harm and treats participants fairly. Ethical weakness can harm participants and also damage data quality because people may withdraw or answer dishonestly.
Do not award automatic praise simply because permission was mentioned. Explain what the permission protects or why it supports ethical practice.
Balance Strengths And Weaknesses
A top response normally explains a range of strengths and weaknesses. Do not force an equal number if the source is clearly stronger or weaker in one direction, but show that you can evaluate more than one aspect.
Possible Order
- State the research purpose.
- Explain two or three weaknesses.
- Explain one or two strengths.
- Finish with an overall judgement about how far the evidence supports the conclusion.
Original Practice Task
Research Description
A student investigates whether residents support a new public park. She asks 25 people leaving a nearby gym to complete a five-question survey. The survey is anonymous. One question asks, “Do you support the beautiful park that will make our neighbourhood healthier?” She records all responses in a spreadsheet and compares them by age.
Evaluation Points
- Anonymous responses may encourage honesty.
- Recording responses in a spreadsheet may improve organisation and reduce loss of data.
- The sample is small for a claim about all residents.
- People leaving a gym may value health and green space more than the wider population.
- The question is leading because it uses positive language.
- Comparing by age may reveal differences, but other important groups or locations are not represented.
Common Mistakes
- Writing a list of features without explaining effects.
- Calling a source biased without identifying the source of bias.
- Assuming large automatically means representative.
- Judging a method without relating it to the research purpose.
- Discussing only weaknesses.
- Suggesting improvements when the question asks for evaluation, without first explaining the weakness.
- Repeating the source instead of judging it.
Exam Checklist
- I identify the purpose before evaluating the method.
- I explain why a sample is or is not representative.
- I identify specific sources of bias.
- I evaluate question wording and data-collection conditions.
- I include strengths as well as weaknesses.
- I link each point to reliability, validity or usefulness.
Lesson Summary
- Evaluation explains the effect of a research feature, not merely its presence.
- Every point should connect to the purpose or conclusion of the research.
- Sample size and representativeness are different issues.
- Methods should be judged according to the type of evidence needed.
- Triangulation can strengthen confidence by checking evidence across sources or methods.
- Strong responses consider a range of strengths and weaknesses.
