In addition to the four golden rules of progressive discipline, there are other considerations you need to make on a case-by-case basis.
Review this ‘‘litmus test’’ any time you’re about to engage in the
disciplinary process:

You’ve got to be consistent in the application of your own rules. In other words, look not only to your written policies but also to your past practices when handling similar types of offenses.
The discipline must be appropriate for the offense. Be sure to fit the company’s response to the seriousness of the infraction.
Employees should be given an opportunity to respond. Each employee deserves to tell her side of the story before disciplinary action is taken. Therefore, as a general rule, you should conduct the meeting first, explain the purpose of the meeting, listen to the employee’s side of the story, and then write the disciplinary memo. You should also encourage em ployees to document their version of the story for the record. Include a sentence in the written warning that states:

I recognize that you may have your own ideas for improving the
situation at hand. Therefore, I encourage you to provide your
performance improvement plan input and suggestions on a separate
sheet of paper if you wish.

Discipline can’t be administered in a vacuum. Disciplinary memos must be tied logically to prior written records in an employee’s file. Therefore, always review prior warnings and performance reviews, and acknowledge consistencies and discrepancies in prior records.

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Remember one additional rule that will always help you administer
discipline fairly. Always ask yourself, How would I respond if my
best-performing employee committed the same error? If you would
respond the same way with your best performer as you would now
with an employee who’s having difficulty meeting job expectations,
then you know that you’re responding fairly. On the other hand, if
it appears that you may be acting more harshly with your current
worker than you would with others, then reconsider your actions
before moving forward.

A caveat here, of course, is that similar infractions need not be
handled identically. You reserve the discretion to consider an employee’s prior service, overall performance, and prior discipline
when evaluating new infractions. For example, a newly hired employee who engages in inappropriate workplace conduct by offending someone’s ethnicity or sexual orientation may be dismissed
immediately. That same behavior from a ten-year employee without
similar prior incidents may merit a written or final written warning
instead of outright discharge. It’s your responsibility as the employer
to match the discipline to the offense

Taken From : The Hiring and Firing Quention and Answer Book