Define the problem
Describe the real-world issue, who it affects, what is already observed, and why the unanswered part matters.
Quality check: Keep the problem specific enough to investigate—not a whole field of study.RESEARCH GUIDE / 01
Study design is the structure connecting a research question to credible evidence. A strong design makes the population, measurements, comparisons, timing, ethics, and analysis clear before data collection begins.

Follow the reasoning
Start in order, but do not treat research as a straight line. Later evidence often sends you back to fix an earlier decision—and that is part of doing the work properly.
Describe the real-world issue, who it affects, what is already observed, and why the unanswered part matters.
Quality check: Keep the problem specific enough to investigate—not a whole field of study.Name the population, main exposure or intervention, comparison where relevant, outcome, place, and time period.
Quality check: A focused question makes the literature search, variables, and analysis easier to align.Use one overall objective and specific objectives that each lead to a measurable result. Add hypotheses when the study will test relationships or differences.
Quality check: Avoid objectives that introduce concepts not present in the main question.Select a cross-sectional, case-control, cohort, experimental, qualitative, mixed-methods, or other design based on the question—not convenience alone.
Quality check: Descriptive questions, causal questions, and lived-experience questions require different designs.Define eligibility, sampling frame, sampling method, sample size reasoning, recruitment, and how non-response will be handled.
Quality check: The people you can reach are not automatically the population you want to understand.Define every key variable, choose valid measurement tools, identify likely confounders, and map each objective to an analysis before collecting data.
Quality check: Include ethics, data protection, bias control, limitations, and a realistic timeline.See it in context
An analytical cross-sectional survey could estimate the prevalence of late-night use and test its association with a measured sleep-quality score at one point in time.
Registered university students meeting stated eligibility criteria
Frequency or duration of smartphone use after a defined night-time hour
Sleep quality measured with a stated, appropriate instrument
Age, course workload, caffeine use, living arrangement, and other justified factors
Descriptive summaries followed by an appropriate adjusted regression model
A cross-sectional design cannot establish which behaviour came first
Before you move on
The question names a population and a measurable outcome.
01The design matches the type of question being asked.
02Eligibility, sampling, and sample-size reasoning are explicit.
03Every objective maps to variables and a planned analysis.
04Bias, confounding, ethics, privacy, and limitations are addressed.
05A sophisticated analysis cannot rescue a design that collected the wrong evidence.
Follow the next decision
A good question should shape the literature search; the evidence should sharpen the design; and the methods should make the result possible to understand and challenge.