Chi-Square Test in SPSS: How to Run and Interpret


 

If your thesis involves two categorical variables, for example gender and study-mode preference, the chi-square test in SPSS is the tool you will reach for. It tells you whether the two variables are related or whether the pattern you see could just be chance. This guide walks you through running the test in SPSS, checking its assumptions, and interpreting and reporting the output in APA 7th style, with a worked example you can follow line by line.

What Is a Chi-Square Test in SPSS?

A chi-square test of independence checks whether two categorical variables are associated. In SPSS it is run through the Crosstabs procedure, which builds a contingency table and tests whether the observed cell counts differ significantly from the counts you would expect if the two variables were unrelated.

For example, a psychology student might ask: is there a relationship between students' year of study (first year, final year) and their preferred counselling format (in person, online)? The chi-square test in SPSS gives a clear yes-or-no answer, plus the numbers you need for your results chapter.

When Should You Use a Chi-Square Test?

Use a chi-square test of independence when all of the following are true:

  • You have two categorical variables, such as gender and employment status.
  • Each observation belongs to exactly one cell of the table, meaning observations are independent of one another.
  • Your sample is large enough: at least 80 percent of the expected cell frequencies should be 5 or more, and no expected cell count should be below 1.
  • Your data are frequencies or counts, not scores or measurements. If your variables are continuous, you need a t-test, ANOVA, or correlation instead.

If the expected-count assumption fails, SPSS output will warn you, and for a 2 x 2 table you should report Fisher's exact test instead. More on that below.

How to Run a Chi-Square Test in SPSS (Step by Step)

Open your dataset in SPSS and follow these steps:

  1. Go to Analyze > Descriptive Statistics > Crosstabs.
  2. Move one categorical variable into the Row(s) box and the other into the Column(s) box. It does not matter which goes where.
  3. Click Statistics, tick Chi-square, and click Continue. You can also tick Phi and Cramer's V if you want an effect-size measure.
  4. Click Cells, tick Expected under Counts so you can check the expected-count assumption, and click Continue.
  5. Click OK.

SPSS will produce two key tables: the Crosstabulation table showing observed and expected counts, and the Chi-Square Tests table containing your test statistic.

Interpreting Chi-Square Output in SPSS: A Worked Example

Suppose a researcher surveys 120 university students about their year of study and their preferred counselling format. The SPSS output looks like this:

Crosstabulation (observed counts)

Year of StudyIn personOnlineTotal
First year382260
Final year243660
Total6258120

Chi-Square Tests table

TestValuedfAsymptotic Significance (2-sided)
Pearson Chi-Square6.8501.009

Read the output in this order. First, glance at the footnote under the table: if zero cells have an expected count below 5, the assumption holds and you can trust the Pearson chi-square row. Second, look at the Pearson Chi-Square row: the value is 6.850 with 1 degree of freedom and a p-value of .009.

Because .009 is smaller than the usual .05 threshold, you reject the null hypothesis. There is a statistically significant association between year of study and preferred counselling format. The crosstab shows the direction: first-year students lean toward in-person counselling while final-year students lean toward online sessions.

One caution: a significant chi-square result tells you the variables are related, not why. It does not establish cause and effect, and it does not tell you the strength of the relationship. For strength, check Cramer's V in the Symmetric Measures table if you requested it.

How to Report a Chi-Square Test in APA 7th

APA 7th reports the chi-square statistic, degrees of freedom, sample size, test value, and p-value in one compact format:

chi-square symbol (df, N = sample size) = value, p = .xxx

Using our worked example, the results sentence would read:

"A chi-square test of independence showed a significant association between year of study and preferred counselling format, chi-square(1, N = 120) = 6.85, p = .009."

A few APA formatting rules to remember: italicize the chi-square symbol and the p, round the test value to two decimal places, and report exact p-values (write p = .009, not p less than .01) unless p is below .001, in which case write p less than .001. Never write p = .000, even if SPSS prints .000; that just means the value rounded to three decimals.

Common Mistakes Students Make with the Chi-Square Test

The most frequent error is ignoring the expected-count assumption. If SPSS warns that more than 20 percent of cells have expected counts below 5, the Pearson result is unreliable. For a 2 x 2 table, switch to Fisher's exact test, which SPSS reports in the same table. For larger tables, consider collecting more data or collapsing categories.

Other mistakes include running a chi-square test on continuous variables such as test scores, treating a significant result as proof of causation, and forgetting to report the sample size and degrees of freedom. Examiners look for all of these details, so double-check each one before you submit your results chapter.

Final Checklist Before You Move On

  • Both variables are categorical and observations are independent.
  • Expected-count assumption checked and satisfied.
  • Pearson chi-square value, degrees of freedom, sample size, and p-value copied correctly.
  • Results reported in APA 7th format with a one-sentence interpretation.
  • Direction of the association described using the crosstabulation table.

Master the chi-square test in SPSS and one of the most common analyses in student research becomes routine. Practice on the worked example above with your own variables, and Chapter 4 will practically write itself.

Need help with your thesis or SPSS analysis? WhatsApp Farzana at +92 326 2047345.

Struggling with SPSS for your thesis? Get the step-by-step guide SPSS Made Simple - 30-page ebook + Excel templates pack. Buy it here: https://whop.com/researchmadesimple/spss-made-simple-a-step-by-step-guide-for-psychology-social-science-students/


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