When analyzing the opinion-based data, the data provided from 28
project managers was included. Because the categories are not
evenly divided, they are considered nominal and cannot be treated
like continuous data. Hence, the responses were ranked from 1 [Far
worse than average (>20% more injuries/risk)] to 7 [Far better than
average (>20% fewer injuries/risk)], and the Spearman rank order
test was conducted. The Spearman rank-order correlation coefficient
(Spearman-r) is a measure of association between two variables
measured on an ordinal scale. The p-values indicate whether
or not to accept the null hypothesis that there is no correlation.
Having p-values close to zero indicates a high level of confidence
that the null hypothesis is incorrect. That means that a p-value of
less than 0.05 indicates a correlation between two values categories.
The Spearman-r correlation results show that there is a relationship
between the overall perception of safety and quality on a project.
The less rework performed, the lower the probability of injuries
or risks.