Which type of data would enhance the validity of incident measures of training effectiveness?

Incorporating data for close calls into incident measures of training effectiveness enhances the validity of these measures because close calls, or near misses, provide valuable insight into the effectiveness of safety training. They represent situations where an incident could have occurred but did not, often due to the implementation of safety protocols or awareness instilled by training.

Collecting data on these occurrences allows organizations to assess how well employees recognize hazardous situations and respond appropriately, which indicates the success of the training provided. Evaluating training effectiveness by looking at close calls can help identify areas of improvement in training programs, thereby fostering a proactive safety culture.

The other options either do not directly contribute to measuring training effectiveness or may limit the scope of the assessment. For instance, excluding data on close calls would omit critical information that reflects the training's impact. Segregating data by type of worker or type of job provides useful insights but does not capture the rich context and learning opportunities that close calls present. Thus, including close call data creates a more comprehensive picture of training effectiveness.