Free Sample Size Software vs nQuery

Why choose nQuery as your statistical sample size calculator when there are freeware options available?

nQuery has thousands of users all over the world and we usually have 500 attendees in our monthly webinars. Because of this we have become synonymous with sample size and study design planning.

This means we are often asked about other sample size options such as freeware for organizations who do not have many trials or do not have the budget for a dedicated sample size and power calculation tool.

A quick online search can show you there are many free sample size calculations tools available. The options range from very simple calculators to more robust R packages and applications like GPower. While a lot of free calculators can be of little use to organizations performing clinical trials tools like GPower can really be quite excellent resources for designing certain types of trials.

Lack of Options

One of the big issues you will encounter with freeware is the lack of options within the tools. They can be fairly useful for the most common trial types however once you get beyond that and add in any layer of complexity they will normally fall down.


In fact we discussed this with so many users we ran a poll to determine what they look for in a sample size calculator. Here are the results of what to look for in a sample size calculator. As you can see many features thought of as standard are not available in many freeware packages.

Can we not just use R?

R is a fantastic resource and is being used more and more by many biostatisticians. One of the major issues with R is replicating results. Of course this is a big problem in terms of Regulatory approval.

Another issue is the amount of work involved and as we have noted from feedback from our users nQuery can provide a 5x improvement on productivity versus coding.

Reducing sample size ethically and responsibly

Clinical trial costs have surged over the past decade, with a report from Medrio stating that from 2008 to 2013, the average cost per patient increased by up to 157%. A major contributor to the cost of a clinical trial is subject recruitment and the associated staff costs. So examining every opportunity to reduce the sample size for a study is an important and necessary step in drug development.

As sample size is such an important part of study design it often makes it essential that you are using a fully validated software package that you can rely on. This means the benefits greatly outweigh having to pay the equivalent of under $50 per month.