Probationary Period
Also called introductory period, trial period, 90 day probation, probation period, initial employment period, evaluation period
Updated August 2, 2026
A probationary period is a defined window at the beginning of employment, commonly 30, 60, or 90 days, during which the employer evaluates whether a new hire can do the job and the new hire evaluates whether the job is what they expected.
In a private at-will workplace it is an internal management practice. It does not create a guarantee of employment for its duration, and completing it does not convert anyone to permanent employment or raise the standard required to end the relationship afterward.
The at-will trap
The risk is the wording, not the practice. Language such as "after successfully completing your 90-day probationary period you will become a permanent employee" implies that employment before that date was conditional and that afterward it is secure. That implication is exactly the kind of promise courts have relied on to find an implied contract, which is why many employers use the term introductory period and state plainly that employment remains at-will before, during, and after it.
What the period is actually for
Stripped of the legal framing, the introductory period is a management cadence. It sets an explicit expectation that the manager will give structured feedback early, that gaps will be named while they are still correctable, and that a clear mismatch will be addressed in weeks rather than at the annual review.
It also functions as a forcing device for onboarding. Naming a checkpoint at 30, 60, and 90 days puts a date on when training should be complete, when the employee should be handling work independently, and when the manager has to make an honest call about fit.
The value comes from the review cadence. An introductory period with no scheduled check-ins is a label on a calendar and nothing else.
What an introductory period can legitimately do
- Set a defined schedule of early feedback conversations, typically at 30, 60, and 90 days.
- Serve as the natural checkpoint for confirming that onboarding, required training, and system access were actually completed.
- Define when certain benefits eligibility begins, where the plan documents use a waiting period.
- Define when paid time off begins to accrue or becomes available for use, subject to state law on accrual and use.
- Give the manager a scheduled moment to decide, rather than letting a poor fit drift into a performance problem.
- Signal to the employee that early questions and course corrections are expected rather than a sign of failure.
Where teams get this wrong
Most of the harm comes from what people believe the period means rather than from the period itself.
- Managers who believe they can terminate freely during probation and need documentation only afterward. Anti-discrimination and retaliation protections apply from day one, and a termination on day 45 is evaluated the same way as one on day 450.
- Managers who believe they cannot terminate during probation without completing the full period. The opposite error, and it keeps clearly unworkable hires in place for weeks.
- Using the word permanent anywhere in the policy or the offer letter.
- Conflating the introductory period with the benefits waiting period. They are set by different documents and do not have to be the same length, and treating them as one thing creates coverage errors.
- Extending probation as an informal substitute for a performance improvement plan, without documented expectations.
- Skipping the check-ins and then terminating at day 89 with no record of any feedback having been given.
- Applying the period inconsistently across similar hires, which turns the practice itself into a comparison point.
Where probation does carry legal weight
The term means something different outside private at-will employment, which is a large part of why it is so widely misunderstood.
In unionized workplaces, a collective bargaining agreement commonly provides that employees may be discharged during a probationary period without the just cause protections and grievance rights that attach afterward. There the period is a genuine legal boundary defined by the agreement.
In public sector employment, civil service rules frequently establish a probationary period after which an employee gains procedural protections against removal.
Montana is the notable private sector exception. Its wrongful discharge statute limits discharge to good cause once an employee completes the applicable probationary period, which makes the definition and length of that period operationally significant there in a way it is not elsewhere.
Why it matters operationally
The introductory period is worth keeping if it drives a real review cadence and worth removing if it exists only as a phrase in the handbook, because in that case it carries the legal downside with none of the management benefit.
The practical test is simple. If a manager can point to what happened at the 30 and 60 day checkpoints for their last three hires, the period is doing work. If not, what the organization actually has is a paragraph that undercuts its at-will language.
Who this applies to
Meaning differs sharply by setting. In public sector and unionized workplaces probation can carry defined legal effect. In private at-will employment it is generally an internal practice.
Common questions
Can we terminate someone during a probationary period without documentation?
Anti-discrimination and retaliation protections apply from the first day, so the reason still has to be lawful and you still need to be able to state it. Documentation is what makes that possible, and a termination with no record of feedback is harder to explain, not easier.
Should we call it probationary or introductory?
Many employers prefer introductory period because probationary implies a status change at the end. What matters more than the word is the surrounding language: state clearly that employment is at-will throughout and avoid any suggestion of permanent status.
Does the probationary period control when benefits start?
Not by itself. Benefits eligibility is set by the plan documents, which use their own waiting period. The two are often the same length by convention, but they are separate and should be described separately.
Can we extend a probationary period?
You can as a management practice, but ask what it accomplishes. If the concern is performance, a documented improvement plan with specific expectations and a review date is clearer for the employee and a better record than an open-ended extension.
Do we need a probationary period at all?
No. Some organizations drop it and instead schedule structured 30, 60, and 90 day check-ins, which delivers the management value without the language risk. The check-in cadence is the part that produces the benefit.
Sources
- Wrongful Discharge From Employment Act — State of Montana (Mont. Code Ann. § 39-2-901)
Related
Related terms: introductory period, benefits waiting period, just cause, 90 day review