Research positions from home may require a range of skills. You may need to be a specialist in a given field or you may simply need to know how to find certain kinds of information.
Researchers do a broad range of work. Mystery shopping is one kind of research. Other kinds of research may involve going to the courthouse to do genelogical research or background checks.
Other research may be done online. You might be doing market research for a company by contacting people or doing interviews. You could be helping companies in a specialty you have a great deal of familiarity with, using databases or other tools.
How much work you receive will generally depend on both your skill and your degree of experience. Companies always prefer to use someone they know is likely to produce quality work than someone who is unknown. It therefore takes time to become established in most research jobs. Upon hiring, you may be tested, and you should expect your work to be reviewed for quality.
Sometimes you will have regular work as a researcher, such as for ongoing projects, but you should expect that many assignments will be short term and that there will be times where you do not have any work coming in. However, you have complete flexibility in deciding whether or not to accept a research assignment. Once you have accepted, however, you do need to finish within the time specified.
Research can be one of the more flexible work at home jobs available, but it can also be quite challenging to get enough work to earn the income you require.