Deciding how many focus groups you need for your project can be tricky. How in-depth are the needs of the project you are working on? Sometimes, it may be more effective to conduct more personal interviews known as individual depth interviews (IDIs). It may also be more cost-effective to do telephone interviews with respondents (TDIs).
If you are looking for more details and want to have more flexibility in your interview, you may decide to go with an IDI. When the product or service you are researching needs you to evaluate complex ideas or concepts, your respondent may need more concentration and focus that is not available in a larger group of people. It is also better to have one-on-one interaction with people if the topic tends to be highly emotional. You will want to be able to establish a relationship that allows you to dig deeper and understand the nuances and insights.
A TDI is also a great way to have access to interviews and respondents that you might not be able to get locally. Having a broader research pool is definitely the highlight of this method, as well as the cost savings of travel. This is also a good way to cover topics that people might be embarrassed to talk about in a group or in person. The downside is that the interviewer loses the ability to read non-verbal cues, which can provide critical feedback.
These interviews can last between 30 and 90 minutes and you will probably have to conduct anywhere from 12 to 60 sessions. This may seem daunting but if cost is a key concern, these types may be the best option to get your data.