Since 2013, I’ve been maintaining a chart on the key book publishing paths for authors. My goal is to help people cut through the confusion of the increasing number of options available—from traditional publishing to self-publishing, and everything in between.

It’s that in between part that’s vexing. It’s become nearly impossible to categorize certain publishers and services; some wish to avoid being labeled altogether. They consider themselves innovators, providing an important alternative for authors. Some in the industry have been using the label hybrid publisher for these services, but that’s no help—not when every hybrid has a different business model.

Authors need specialized knowledge of the industry to evaluate these hybrids effectively and to understand the underlying value of a service and whether it has the power to make a difference in their book’s success. Here are questions I use to help authors evaluate their choices (I will be using the terms publisher and service interchangeably):

Will there be a traditional print run—and who’s paying for it?

A print run equates to an investment—someone is taking a financial risk on the book’s success. Having a specific number of books printed anticipates sales and marks confidence that the book will be actively stocked in bricks-and-mortar stores. Authors shouldn’t pay for their own print runs unless they know exactly how and to whom those books will be sold.

Will the book be pitched to retailers or distributors by a sales team?

This means that the publisher calls on specific retail accounts and distributors to secure orders for the book in advance of publication. This step is very unlikely unless there’s investment in a print run as well as a marketing plan.

How will your books be distributed?

Anyone can get a book distributed through Ingram and Amazon via print-on-demand, as long as the files meet certain basic standards. If your book is listed via Ingram, all book retailers can place orders for it. (That doesn’t mean your book will ever sit on a physical shelf, but it can be ordered through a store.) If a publishing service touts being distributed through Ingram, that’s not necessarily a selling point—you can do that on your own.

It’s rare for pay-for-play services to actively sell and distribute physical copies to bookstores, which is costly and requires industry contacts. (A few are Greenleaf Book Group, She Writes Press, InkShares, and Matador.)

But print distribution isn’t the only reason to work with a hybrid publisher. In the case of firms that focus on e-book distribution, authors must assess their own strengths and consider whether their books would be more successful if they had a service partner supporting them.

When evaluating a service, look for signs that it will be a good business partner and likely to produce a successful book. Due to the extreme ease of publishing and distributing books in digital format, anyone can put out a shingle and call him- or herself a publisher. So here are some additional questions to consider:

What’s the editing process like?

Some services will take exactly what you give them and publish it, without any editing. Even if that sounds appealing, this shows a lack of professionalism. Virtually no manuscript is ready for prime time without some editorial work.

What marketing and promotion support do their titles receive?

Ask what the service’s baseline marketing plan is for each title. Does it send out review copies? Does it write a press release? Does it submit the book to media outlets for coverage? Find out the bare minimum it commits to, and if it does little more than make the title available for sale, rethink why you want to publish with it.

Can you speak to recent authors?

This can be the best litmus test of all. Are other authors pleased with the publisher’s communication and level of involvement? How much value did the publisher add to the process?

Finally, before committing to any service, get clear answers on costs, and read your contract carefully. If things go wrong, know when and how you can hit eject (and at what cost) so you can pursue a better path.

Jane Friedman teaches digital media and publishing at the University of Virginia and is the former publisher of Writer’s Digest.