Data Analysis

Dissertation Data Analysis: Choosing Tests and Writing Your Results Chapter

How to pick the right statistical test or qualitative method for your research questions, run it correctly, and report it in a results chapter your committee will accept.

Updated October 2026 · 9 min read

Data analysis is where many dissertations stall. The data is collected, the methodology chapter is approved, and then the questions start. Which test answers my research question? Do I need to check assumptions? Why does SPSS give me three different tables? How do I write this up without interpreting it?

This guide works through those questions in the order you will meet them: matching each research question to a method, preparing and checking the data, running the analysis, and reporting it in a results chapter (usually Chapter 4) that your committee will accept.

It covers quantitative and qualitative analysis, and it explains what an analyst can and cannot do for you.

How to choose your tests

Start from your research questions and hypotheses, identify the type of each variable, and choose the test that fits that combination (for example, an independent t-test for comparing two groups on a continuous outcome). Clean and screen the data, check the test's assumptions, run the analysis, and report each result in APA format: the test, the statistic, degrees of freedom, p-value, effect size and a one-sentence plain statement. Save interpretation for the discussion chapter.

Step 1: Build an Analysis Plan from Your Research Questions

Your methodology chapter should already name the analysis. If it does not, or if the data has turned out differently from what you expected, write a one-page analysis plan before running anything. For each research question, record:

This plan keeps you from running every test in the menu and reporting whichever gives a significant result, which committees recognize and penalize.

Matching the Question to the Test

Your questionVariablesParametric testNon-parametric alternative
Do two groups differ?2 independent groups, continuous outcomeIndependent samples t-testMann-Whitney U
Did scores change over time?Same people measured twicePaired samples t-testWilcoxon signed-rank
Do three or more groups differ?3+ groups, continuous outcomeOne-way ANOVAKruskal-Wallis
Are two variables related?Two continuous variablesPearson correlationSpearman correlation
Are two categories associated?Two categorical variablesChi-square test of independence (Fisher's exact for small samples)
What predicts an outcome?Continuous outcome, several predictorsMultiple linear regressionRobust or ordinal regression
What predicts a yes/no outcome?Binary outcomeBinary logistic regression
Do several items measure one construct?Questionnaire itemsCronbach's alpha, exploratory or confirmatory factor analysis

Likert-scale data is a common source of argument. Single Likert items are ordinal and suit non-parametric tests; composite scales built from several items are usually treated as continuous. State your reasoning in the methodology and follow your program's convention.

Step 2: Prepare and Screen the Data

Most errors in results chapters start before the analysis. Work through this list and record what you did, because the results chapter should report it briefly.

CheckWhat to look forTypical action
Data entryImpossible values (age 250, a 7 on a 5-point scale)Correct from source or set to missing
Missing dataHow much, and whether it is randomReport the amount; use listwise deletion, multiple imputation or another method justified in your methodology
Reverse-coded itemsNegatively worded questionnaire itemsRecode before computing scale scores
OutliersExtreme values on boxplots or z-scores beyond about 3.29Check, then keep, transform or remove with a stated rule
NormalityHistograms, Q-Q plots, Shapiro-Wilk (with caution in large samples)Proceed, transform, or use a non-parametric test
ReliabilityCronbach's alpha for each scaleReport alpha; values around .70 or above are usually considered acceptable

Step 3: Run the Analysis and Check Assumptions

Each test has assumptions, and your committee will expect you to have checked them. For example, an independent t-test assumes independent observations, an approximately normal outcome in each group, and similar variances (Levene's test).

Multiple regression adds linearity, independence of errors, homoscedasticity and the absence of severe multicollinearity (variance inflation factors well below 10). When an assumption fails, report it and use the alternative you named in your plan, such as Welch's t-test or a non-parametric test.

Software

SoftwareBest forNote
SPSSMost social science, education, nursing and business dissertationsMenu-driven; save the syntax so the analysis can be reproduced
R or PythonComplex models, large datasets, reproducible scriptsFree; supervisors in quantitative fields often prefer them
StataEconomics, epidemiology, panel dataStrong for regression and survey weights
NVivo, ATLAS.ti, MAXQDAQualitative coding of interviews and documentsSoftware organizes coding; it does not do the analysis for you

Step 4: Report Results in APA Style

Report each result the same way: the test, the descriptive statistics, the test statistic with degrees of freedom, the exact p-value, an effect size with its interpretation, and one plain sentence saying what was found.

Example: An independent samples t-test showed that nurses on 12-hour shifts reported higher burnout (M = 3.41, SD = 0.62) than nurses on 8-hour shifts (M = 3.02, SD = 0.71), t(186) = 3.98, p < .001, d = 0.58, a medium effect. Hypothesis 1 was supported.

Use tables for anything with more than three or four numbers, such as descriptive statistics, correlation matrices and regression coefficients, and refer to each table in the text without repeating every value. Report non-significant results in the same detail as significant ones.

Effect Sizes to Report

TestEffect sizeSmall / medium / large (Cohen's guidelines)
t-testCohen's d0.2 / 0.5 / 0.8
ANOVAPartial eta squared.01 / .06 / .14
Correlationr.10 / .30 / .50
RegressionR squared, standardized betaInterpret in context
Chi-squareCramér's V or phiDepends on degrees of freedom

Worked Example: From Research Question to Reported Result

Here is how one research question travels through the whole process in a typical education dissertation.

Research question: Is there a relationship between weekly hours of paid employment and academic self-efficacy among community college students, after controlling for age and enrollment status?

Variables: outcome, academic self-efficacy (scale score, continuous); predictor, hours of paid work per week (continuous); covariates, age (continuous) and enrollment status (full or part-time, dummy coded).

Test: hierarchical multiple regression, with covariates entered in step 1 and work hours in step 2.

Checks: scale reliability (alpha = .86), linearity and homoscedasticity from residual plots, VIFs below 2, no influential cases (Cook's distance below 1), 14 cases removed for missing data (5.1%).

Reported result: After controlling for age and enrollment status, hours of paid work explained an additional 6% of the variance in academic self-efficacy, ΔR² = .06, F(1, 255) = 17.42, p < .001. More hours of work were associated with lower self-efficacy, β = −.25, p < .001.

Notice the language: "associated with", not "caused". A correlational design cannot support a causal claim, and committees notice when the results chapter overreaches.

Structuring Chapter 4

  1. Introduction: one paragraph restating the purpose and research questions.
  2. Data screening and sample: response rate, missing data, exclusions, and participant characteristics in a demographics table.
  3. Reliability and assumptions: scale reliabilities and assumption checks, briefly.
  4. Results by research question: one sub-section per question or hypothesis, in the same order as Chapter 1.
  5. Summary: a short paragraph or table listing each hypothesis as supported or not supported.

The rule committees enforce most often: Chapter 4 reports, Chapter 5 interprets. Phrases such as "this suggests", "this may be because" and comparisons with other studies belong in the discussion.

Mistakes Committees Flag Most Often

Methodologists and committee members see the same problems in results chapters year after year. Checking your draft against this list before submission saves a round of revisions.

MistakeWhy it is a problemFix
Running many tests and reporting only the significant onesInflates false positives and looks like p-hackingReport every planned test; correct for multiple comparisons where appropriate (for example Bonferroni or Holm)
Writing "p = .000"A p-value is never exactly zeroReport p < .001
No effect sizesSignificance alone says nothing about practical importanceReport an effect size for every test
Treating "not significant" as "no difference"Absence of evidence is not evidence of absence, especially in small samplesSay the difference was not statistically significant and discuss power in Chapter 5
Pasting raw SPSS tablesDefault output is not in APA format and includes irrelevant rowsRebuild tables in APA style with only the values you discuss
Changing the analysis without saying soCommittees compare Chapter 4 against the approved planExplain any deviation from the proposal and why it was necessary
Interpreting in Chapter 4Blurs results and discussionMove explanations and comparisons with the literature to Chapter 5

Qualitative Analysis

Qualitative dissertations need just as much rigor, but the steps differ. Thematic analysis following Braun and Clarke's six phases is the most common approach: familiarization, initial coding, generating themes, reviewing themes, defining and naming themes, and writing up.

Other approaches include interpretative phenomenological analysis, grounded theory and content analysis; each has its own procedures, so use the one named in your methodology.

A qualitative findings chapter is organized by theme, with each theme defined, explained and supported by participant quotations that show its range.

Include a table of themes and sub-themes, and describe how you established trustworthiness: an audit trail, member checking, reflexive notes, or a second coder. For a deeper treatment, see our guide to qualitative research methods.

How Long Each Stage Takes

StageClean survey data, 2-4 testsComplex models or messy dataQualitative, 10-20 interviews
Analysis plan1 day2-3 days1-2 days
Cleaning and screening1 day3-5 daysTranscription checks, 2-4 days
Analysis1-2 days4-7 daysCoding and theme development, 1-2 weeks
Write-up and tables2-3 days4-6 days4-7 days

Build in time for your chair's feedback. Results chapters are commonly revised at least once, often because the committee wants an additional check or a different presentation of a table.

What an Analyst Can Do, and What Stays Yours

Can doMust stay yours
Write or refine the analysis planThe data, collected as approved by your ethics board
Clean, code and screen your datasetDecisions your committee has already approved
Run the tests and check assumptionsUnderstanding of what was done, so you can defend it
Produce APA tables and the results write-upThe interpretation in your discussion chapter, informed by your field knowledge
Explain the output in plain language

Results are always produced from your real data. No reputable analyst will fabricate or adjust data to reach significance, and doing so is research misconduct.

What to Send

You receive the results write-up, the tables, and the output or syntax files, so you can show exactly what was run.

Get Your Results Chapter Done Properly

Send your dataset, research questions and methodology. A statistician runs the right tests on your data and reports them in APA style, with output files included.

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Frequently Asked Questions

Which statistical test should I use for my dissertation?

It depends on your research question and the type of variables. Comparing two groups on a continuous outcome suggests a t-test; three or more groups suggests ANOVA; relationships suggest correlation or regression; categorical associations suggest chi-square. Your analysis plan should justify the choice.

What if my results are not significant?

Report them fully and honestly. Non-significant results are still findings. Discuss possible reasons, such as sample size or measurement, in Chapter 5, and never change the analysis just to reach significance.

Can you analyze data I collected with a survey?

Yes. Send the dataset and the questionnaire. Scale scores, reliability, descriptive statistics and the tests that answer your research questions can be run and reported in APA style.

Do I get the SPSS output?

Yes. You receive the output and syntax or script files along with the write-up, so the analysis can be checked and reproduced.

Is Chapter 4 the same as the discussion?

No. Chapter 4 reports what the data shows. Chapter 5 interprets the findings, compares them with the literature and states implications.

How long does dissertation data analysis take?

A straightforward quantitative analysis with a clean dataset can take a few days. Complex models, messy data or qualitative coding of many interviews take longer, often one to three weeks.