Final answer:
The most suitable metric for measuring workforce effectiveness in a call center focused on completing sales per call is 'C. Revenue per employee', which aligns with productivity and profitability indicators.
Step-by-step explanation:
To measure workforce effectiveness in a call center that depends on sales completed per phone call, where employee's ability to establish credibility and achieve customer satisfaction are critical, the most appropriate metric would be C. Revenue per employee. This metric aligns closely with both productivity and profits, reflecting the effectiveness of training and skill levels of the employees. According to a 2003 study by Arthur, Bennett, Edens, and Bell, organizational training effectiveness can be assessed by measuring immediate employee response, learning outcomes, supervisory evaluations of job activities, and results such as productivity and profits. Enhancing employees’ skills and education, known as human capital investment, directly contributes to increased productivity which in turn affects the firm's profitability and workforce effectiveness.