- The level at which statistical significance occurs from a finding.
- It reflects the strength of the results found in a study and determines the likelihood that the results were due to chance.
- A p-value of < 0.05 simply means that the probability the results were due to chance or random error is < 1 in 20 or < 5%.
- The smaller the p-value, the lower the likelihood the results found in a study were due to chance or random error - or - said another way, "the smaller the p-value the more likely the results found from a study are real"
- This is why researchers hope or desire to have small p-values
- It is important to know that the p-value does NOT tell you anything about the:
- Clinical significance of the findings
- Size of the effect found
a study was completed and found that the two interventions being evaluated were
statistically different and reported a p-value of 0.01, then we can say that there is
a 1% chance that those results found in this study are either due to chance or
- It is important to remember these two things:
- The lower the p-value the lower the likelihood of the results occurring from chance.
- The p-value does not tell you anything about the clinical significance of those results - that is for clinicians to decide for themselves.
What is a P-value?