Sometimes you might feel uncomfortable with an estimate. Sometimes, no matter how confident you are in an estimate, you’ll present it to the customer or management and receive considerable pushback leaving you doubting your estimating expertise. You – or others – start to suspect that the estimate is unrealistic. Reasoning or assumptions may have been faulty.  Calculations may be inaccurate. Maybe you’ve lost confidence in the person or individuals who provided the estimate. Whatever the reason, you can take several actions to validate the estimate.  Let's look at five different options for re-evaluating estimates...

Check historical records

A search of previous projects can often unearth similar work efforts. The key is to know not only the old estimate but also what the actual dollars were that ended up being associated with that original effort. If you can find that information, that will likely provide you with the best possible cross-reference to the new work that you’re trying to come up with an accurate estimate for. As you search, keep in mind that often such data is either difficult to obtain or may even be completely unavailable.

Seek a second opinion

Another option you can always use is to seek a second opinion. This is a good choice when you’re surrounded by development staff and you’re running an IT project – plenty of options for second opinions. It would probably be best if you went to someone on another project where similar work was performed or is currently being performed. If these options aren’t possible, it might mean going to an outside expert or organization for evaluation.

Benchmark tasks

Another option available to you when you are evaluating or re-evaluating an estimate is to go to the effort of benchmarking one or more tasks. It may mean comparing the estimates with similar ongoing or completed projects, either inside or outside your company. Either way, it can give you a great frame of reference for calculating the overall larger set of tasks in question.

Apply the Delphi approach

A fourth option is the application of the Delphi approach. Simply identify a number of people to provide input on an estimate. Then make the adjustment and resubmit the estimate to them for further adjustment. The adjustment ends once you gain concurrence or are comfortable with the result.

Conduct peer reviews

A final option to consider is the conducting of peer reviews. Once all the estimates are complete, you can assemble everyone in a room to discuss the estimate for each task. Assumptions and issues may arise that will call into question the validity of some estimates. New estimates can then be developed.