Understanding Statistical Significance in Survey Results
Updated: Jul 6
In the realm of research and surveys, statistical significance plays a crucial role in determining the reliability and validity of findings. It helps us understand whether the observed results are due to chance or represent true effects in the population under study. In this blog, we will delve into the concept of statistical significance, its importance, and how it applies to survey results. It can be confusing and misinterpreted in its meaning.
So, what is Statistical Significance?
Statistical significance is a measure used to determine if an observed difference or relationship between variables in a sample is likely to represent a genuine effect in the wider population, rather than just random chance. It provides a way to assess whether the findings of a survey are meaningful or if they could have occurred by mere coincidence.
The Importance of Statistical Significance
Statistical significance is important for several reasons:
Confidence in Results: When surveying a subset of a larger population, we want to have confidence that the observed results accurately reflect what we would find if we surveyed the entire population. Statistical significance helps us determine the likelihood that the observed results are representative of the population as a whole.
Informed Decision Making: Policy-makers, researchers, and businesses rely on survey results to make informed decisions. Statistical significance enables us to distinguish between meaningful findings and random noise, helping us avoid making decisions based on unreliable or chance associations.
Generalising: Statistical significance allows us to generalise findings from a sample to a larger population. If a survey yields statistically significant results, we can confidently infer that similar patterns or relationships would hold true for the entire population.
Calculating Statistical Significance
The calculation of statistical significance involves comparing the observed results with what would be expected to occur by chance alone. This is typically done using statistical tests, such as the chi-square test, t-test, or analysis of variance (ANOVA), depending on the nature of the data and research question.
The statistical test produces a p-value, which represents the probability of obtaining results as extreme as or more extreme than the observed results if there were no true effect in the population. A common threshold for statistical significance is a p-value of 0.05 (5%), meaning that there is a 5% chance of obtaining such results by chance alone.
Interpreting Statistical Significance
If the p-value is below the chosen threshold (e.g., p < 0.05), the results are deemed statistically significant. This indicates that the observed findings are unlikely to be due to chance alone and suggest the presence of a genuine effect in the population. Conversely, if the p-value exceeds the threshold, the results are considered not statistically significant, implying that the observed results may have occurred by chance, and the relationship or difference might not exist in the population.
Limitations and Considerations
While statistical significance provides valuable insights, it is essential to consider its limitations:
Sample Size: Larger sample sizes tend to yield smaller p-values, making it easier to detect statistically significant effects. Therefore, sample size should be considered when interpreting the results.
Practical Significance: Statistical significance does not necessarily imply practical or meaningful significance. A small effect size might be statistically significant, but it might not have real-world significance or impact.
Statistical significance is a vital concept in survey research, helping us determine whether observed results are likely to represent true effects in the population or are simply due to chance. It provides confidence in the findings, aids decision-making, and allows us to generalise conclusions from a sample to a broader population. However, it is crucial to interpret statistical significance alongside other considerations, such as sample size and practical significance, to obtain a comprehensive understanding of the results. By embracing statistical significance, we can make more reliable and informed conclusions based on survey data.