Which of the following are appropriate ways to measure an employee’s performance?

a. Day after day, more than three customers are lined up at Janet’s cash register, so her supervisor concludes that she is a slow worker.

b. Jonathan smiles a lot, so his supervisor assumes he is happy.

c. Wesley is late to work every Wednesday morning, so his supervisor plans to find out the cause.

d. Nick habitually takes longer to deliver pizzas than his company promises its customers, so his supervisor notes that he is inefficient.

e. Production in the group that Caitlin oversees has fallen off somewhat in the last two months, so her supervisor discusses with her the possible reasons.