Assessing performance is tricky but crucial—so much rides on it. In his latest book, How to Be Good at Performance Appraisals, Dick Grote tells us how to manage a company’s most valuable resource—people. This step-by-step guide comes with dos and don’ts, role-play scripts and tips on tackling difficult situations, such as determining compensation and letting go of poor performers. Grote, president of US-based Grote Consulting Corp., which offers expertise in appraisals and talent management, has previously written The Complete Guide to Performance Appraisal; Forced Ranking: Making Performance Management Work; and Discipline Without. In an email interview, he explains the nitty-gritty of appraisals. Edited excerpts:

What is the right balance between a quantitative and qualitative review?

Let me give you two answers to this. First, there are only four measures of output: quantity, quality, cost and timeliness. All four should be considered when a supervisor assesses performance. If we are measuring the amount of work someone has done (quantity), or whether she met the project deadline (timeliness), or whether he was under budget/on budget/over budget (cost), we will be able to find quantitative, numerical metrics very easily.

Skip the ‘Sandwich Technique’: The message should be clear and straightforward.

Then I ask them, “While the answer will certainly vary depending on the specific job, what general recommendation would you give managers about what percentage of a performance appraisal rating should be based on the results a person achieves and what percentage should be based on his or her behaviours?" Almost universally, the answer is the same from every group: 60% on results; 40% on behaviours. That strikes me as a good starting point in figuring out where to put the emphasis on any particular job.

360-degree feedback seems a fairly balanced and effective way of appraisal. Why don’t firms use it more?

I’m afraid I must disagree. Actually, 360-degree feedback data is useful primarily for helping a person who is already a successful, solid performer understand his or her developmental needs, and is not a good tool for performance appraisal. Here’s why. First, there is the problem of the “infinite human capacity for self-delusion". We all think we’re really better at doing anything than we really are. We tend to be blind to our shortcomings, and the more weaknesses we have, the more blind to them we are. Research shows an individual’s immediate supervisor is the best person to evaluate his performance. If we allow others to have a voice in a person’s rating, we run into a difficult ethical problem. Many of the respondents may be competing with the individual being reviewed for a promotion or a salary increase.

Finding the right man for the right job: what role does appraisal play in this?

How to Be Good at Performance Appraisals:Harvard Business Review Press, 218 pages, 750.

Should we really focus only on strengths? How can negative feedback/confrontation be tackled?

For 50 years, the usual practice is that managers have been told to use the“Sandwich Technique": Start by discussing the person’s strengths and accomplishments, then switch over and talk about deficiencies and improvement needs, then close the meeting by once again talking about strengths. This is a bad approach. It forces the manager to deliver a mixed message: some good stuff, followed by some bad stuff, ending with some more good stuff. Nobody gets a clear, straightforward message.

Here’s my recommendation. If you’re talking with a good solid performer or a star, focus exclusively on reviewing the individual’s successes and thanking the person for his or her contributions. Let the employee be the one to bring up problems or improvement needs (they will).

But if you’re dealing with a poor performer, someone who needs to improve his or her performance significantly, focus exclusively on the needs for immediate problem-solving and performance improvement. In this way there will be no misunderstanding of the message.

Is compensation the underlying reason for all appraisals?

No. Performance appraisal can give us the vital information we need to make wise compensation decisions, and that is one of its most important uses. Performance appraisal is also a vital tool for determining an individual’s development needs, and for identifying who’s ready for promotion, and for supporting a decision to terminate an employee, and many other important business decisions.

But for me, the most important reason we do performance appraisal is that it is a leadership obligation. Every person who works for any organization wants the answers to two questions: 1) What do you expect of me? and 2) How am I doing at meeting your expectations?

So performance appraisal does far more than provide the basis for making compensation decisions. It is an ethical obligation of every person in a leadership position.

Is self-appraisal a good idea?

No. Self-appraisal is a bad idea and needs to be stomped out. By asking an employee to write a self-appraisal, particularly when the company’s appraisal form is used, it’s easy for an employee to assume that the structure of the process is that both the individual and the boss separately write their appraisals of the individual’s performance. They then get together, share each one’s document with the other, and through a kind of mediation process come to a common agreement on the final appraisal.

That’s wrong. Again, the appraisal is a record of the supervisor’s opinion. The review meeting is a discussion, not a negotiation. Asking the individual to write a self-appraisal encourages misunderstanding by both parties.

However, it is valuable to get information from the individual to help the manager create a well-rounded, complete, and objective appraisal, even if writing a self-appraisal on a blank copy of the company’s form isn’t the best way to do it. A more effective approach is for the supervisor, at the start of performance appraisal season, to ask each direct report to send him an informal list of his or her most important accomplishments and achievements during the appraisal period.

The manager’s purpose here is to make sure none of the employee’s successes are overlooked and to get a preview of the employee’s feelings about his own performance. This “good stuff" list will provide the same value as a formal self-appraisal. It will also help remove some of the negativity that surrounds many people’sfeelings about the performance appraisal process.