What is the difference between "private interests" and "parochial interests"?

Solution 1:

Parochial

The term originates from the idea of a parish, one of the smaller sections within many Christian churches (Orthodox, Anglican, Roman Catholic, etc.).

Parochial is not just limited to religious uses. It can be applied in both economics and culture, given that a local geographic area or culture bases all decisions solely on local interests and do not consider the effect of their decisions on the overall broader community. The term can be used to describe schools, neighborhood disputes, and/or churches, for example.

Parochial interests are those that benefit a specific group who shares the same interests but can never describe the interests of an individual. These interests sometimes cause a negative effect on everyone else.

Private

Private Interests, on the other hand, can describe the interests of an individual. While it can describe the interests of an individual, it can also be used to describe a small bound-together group of individuals. This group isn't necessarily a entity together, but are linked for business or personal gain reasons.

Private interests are generally more individual-based, where parochial interests benefit the group as a whole, instead of benefiting the individuals specifically.

Solution 2:

The word "parochial" comes from "pertaining to a parish" — which is the local domain of a particular church. It means that some enterprise or view is narrow or restricted.

In your case, parochial interests mean those interests belonging to a small group that shares a common goal or interest. The term never pertains to an individual. The group can be a large one, though. The interests of Roman Catholics in the United States can be called "parochial" if those interests involve something that is strictly of interest to Catholics.

Private interests, however, can mean the interests of one individual, but can also mean certain individuals bound together in some way, usually involving business or property.

It may be useful to think of the difference this way: private starts at the individual and works outward, but parochial starts with a group, which may be of any size.

Solution 3:

The distinction between private interest and parochial interest can only be made on a situation by situation basis.

If the issue creates an ad hoc group of beneficiaries, often an irregular subset of some larger group, where the beneficiaries do not seem to merit benefits relative to the others, that is private interest. Often private interests revolve around gaining some competitive advantage within the group.

Parochial interests typically revolve around gaining advantages for an entire group. Any member could be assumed to gain thereby. "Parochial" is often used with respect to lobbying groups such as big pharma, the AMA, the ABA, and the insurance lobby.

So the distinction tends to involve the sort of people who benefit, the sort of benefit they receive, as well as the vantage point. From a federal standpoint, state legislatures enact parochial legislation. The style guides I looked at didn't address the issue.

Perception-wise, private interests are often couched as an illegal pursuit, while parochial interests tend to be couched as an unjust pursuit. This habit has a long history going back at least to James Madison and the framing of the US constitution. I'm not sure that the distinction between a constitutional matter and a merely legal one is still in play, but it used to be.