Why a Focus Group shouldn't be used to evaluate usability.

One of the techniques most commonly used by companies and their marketing areas for audience research is the focus group. This technique is characterized by gathering a group of people (not more than 10 or 12) representing a potential customer segment aimed at a particular product or service to ask for their opinion about the characteristics of that product or service.  

Some of the questions that attempt to be answered by a focus group are whether consumers: 

• Would buy a product or service
• Under what circumstances.
• If they like the product or not.
• Why would they choose one product instead of another?
• If they could change something: What would it be and how would they do it?

Focus groups are useful research tools when you want to know opinions of people, their motivations, and expectations for a product or service. 

The main mistake committed in relation to focus groups occurs when opinions expressed by participants are confused by their behavior, that is, what they would do in reality. 

When we need to know what people do or how they use a particular product or service focus groups fail and can be misleading and costly: 

To cite another example, in the book "How Customers Think" Gerarl Zaltman mentions a study where 60% ​​of the people who tried a new kitchen in the context of a product presentation, said they likely or very likely would buy the product the following three months. After eight months, only 12% had bought it. 

When we need to know what people actually do, rather than say, we must observe how they use a particular product or service. In the field of user experience there are two techniques that allow us to find this:

• User testing
• Contextual survey

Both techniques analize people's behavior, not their opinions, and therein lie their value.

When you need to evaluate the ease of use (usability) of an interface, the technique used is user testing. This consists essentially of asking a number of people (interviewed individually) to solve particular tasks with the interface. The researcher observes if the task can be solved successfully, and the difficulties the person may have had during the process. 

In this context, the limitations of focus groups are evident: ask a person if he/she thinks that in the near future he/she will have some problem solving a given task is, at the very least, vague, considering the need any of us has to try and experience ourselves to find out. 

The answer to this question in the context of a focus group would be: the person is not forseeing obstacles or problems for solving the task, and that he/she would "likely" or "very likely" perform successfully.