A case is any stream of activity over time, involving one or more people.
The standard idea of a case involves a client and one or more workers, i.e. volunteers or staff, and perhaps one or more third parties.
But OpenCase is intended to break the stereotype of cases always being about an organisation helping a client, and it uses cases to record any stream of activity. So, in OpenCase, recruiting and training a volunteer is a case; interviewing and taking on a member of staff is a case.
A case has two parts to it - a screen with case details and files, and the stream of activities. Activities are explained here.
The case details are a record of general data about the case. For example: what type of case is it, when did it start, how long is it expected to last, what the desired outcome is, whether it is pro bono or covered by legal aid, who is involved in it, etc. These fields are all configurable because every organisation will have its own needs in regard to what data to record for each kind of case. But some are there by default, to get you started. You can also upload files to cases.
Types of cases
Many organisations do not just provide one type of service but many, and they need to record different data for them. For example as a youth charity you may take some people on for housing advice and others for drug dependency issues. Having different case types means that the case details screen for each type of case will have fields that are relevant to that and not necessarily to others.
Also, sometimes one organisation will do different projects that are paid for by different funders, with different reporting requirements.
Again, although some types of cases are provided by default, you will probably want to create your own or at least make customisation to the them.