i would like to advice a superior to communicate with the 
employee.superior should ask him about his problems. and he 
should understand the causes of employee that why he is not 
performing according to the expectations.
the target is generally decided by having discussions with 
superior and subordinate. and after certain period the 
performance is evaluated.the employee should also 
understand the level of performance expected.supervisor 
should discuss with that employee about his problems & must 
help him in reducing the problems.it ultimately help 
employee to boost his performance& ultimately improve 
organization's productivity.

I would like to advise the supervisor due to the poor 
performance of the employee the following;

1.   Supervisor has to identify the genisis of the problem 
and that has to be evaluated and rectified.

2.    If an employee underperforming due to any reasons, 
there would have some reasons behind it. If it is for 
motivational factor, that has to be taken into account or, 
if it is for some other reasons that would also taken into 
account.

3.    Periodical training of all employee is required which 
will reduce attrition level and would result high 
interpersonal relationship among employeees.