Understanding the Lead Score
March 2026 | User Guides
Every book in Sleuthy’s database has a Lead Score: a single number from 0 to 100 that represents how promising that title looks as a potential audiobook project. It’s the first thing you see in search results, and it’s the default sort order for a reason: it’s designed to surface the best opportunities and push the weaker ones down.
But what does the number actually mean? And how should you use it?
The Three Bands
The Lead Score is colour-coded into three bands to give you an instant visual read:
How the Score Is Built
The Lead Score is built from the ground up using what I call the Audiobook Success Matrix: a framework developed from years of prospecting experience, informed by the data in our annual genre studies. It evaluates each book across multiple factors, grouped into three tiers of importance.
Tier 1: The Killers
How well is this book selling right now? The Amazon bestseller rank is the single strongest indicator of reader demand. A book ranked under 100,000 is selling well. Under 50,000 is excellent. Under 10,000 is elite. A book ranked over a million is a long shot. Free books are scored separately, because their rank is inflated and less reliable.
Not all genres are equal when it comes to audiobook demand. Drawing from our annual Audible genre sales studies, each book’s genre and subcategories are matched against a five-tier strength map. Fantasy and Thriller sit at the top. Romance, Science Fiction, and Personal Development are close behind. Niche categories like Poetry, Travel, and Reference score lower. A strong book in a strong genre gets the full benefit.
Some books simply aren’t suited for audio narration. Colouring books, puzzle books, journals, graphic novels, workbooks, picture books: they might rank well on Amazon, but they’re not audiobook prospects. Sleuthy scans each title and description for these red-flag keywords. Books that pass get full marks. Books that don’t get zero.
Tier 2: Strong Signals
A book rated 4.0 or above on Amazon is in good shape. Below 3.5 suggests something’s off. When Amazon rating data isn’t available, Sleuthy falls back to Goodreads (adjusted upward slightly, since Goodreads ratings tend to run about half a point lower).
Raw review count can be misleading: a book published ten years ago will naturally have more reviews. So the score measures ratings per year instead. A book earning 50 or more ratings per year has healthy, ongoing reader engagement. Under 10 per year is weak. This tells you whether demand is current, not just historical.
There’s a sweet spot for audiobook length. Books between 150 and 350 pages tend to work best: long enough to be a substantive listen, short enough to be a manageable project. Books under 100 pages or over 500 get scored lower, though they’re not ruled out.
Books that are part of a series get a bonus. There’s a momentum effect: if you narrate one book in a series and it does well, the author is very likely to want you for the next one. One relationship, multiple projects. That’s the narrator’s dream.
This factor is reserved for a future enhancement. We’re working on a way to assess cover design quality automatically. For now, it contributes a neutral baseline score.
Tier 3: Supporting Factors
Some books have long tails: they keep selling steadily for years. Others spike and fade. This factor, currently at a neutral baseline, is being developed to identify titles with lasting earning potential.
Research shows that genre ambiguity hurts sales. A book that clearly signals what it is, through its title, cover, and categorisation, tends to perform better. This factor is also being developed for a future update.
Indie and small-press books score highest here, because they’re the ones most likely to be open to narrator approaches and royalty share deals. Major publishers score lower, not because the books are worse, but because the narration rights are typically harder to access. University presses score lowest.
How to Use the Score When Prospecting
For broad searches
Sort by Lead Score (it’s the default) and start from the top. Green scores get your attention first. Amber scores are worth scanning for titles that match your niche even if the overall numbers are more modest. Red scores can mostly be skipped unless you have a specific reason to look deeper, for example, a genre you specialise in where you know the landscape better than any algorithm.
For niche searches
If you’re searching a specific subgenre or using keywords, the Lead Score helps you triage a long result list quickly. In a niche category, even an amber score can represent a strong opportunity, because the genre strength component naturally caps lower. Context matters.
For lead management
When you save a book to your leads list, the Lead Score is displayed alongside it. Over time, you’ll develop an intuitive sense for what scores tend to produce results in your area. Some narrators find their sweet spot is the 50–70 range, books with genuine potential but less competition from other narrators chasing the obvious green-score titles.
What the Score Can’t Tell You
A few things the Lead Score deliberately doesn’t try to measure, because they require human judgment:
Voice fit. A book might score 90 but be completely wrong for your vocal style or range. Always read the description and sample before pursuing.
Rightsholder responsiveness. The score can’t predict whether an author will reply to your email, be open to a royalty share deal, or be pleasant to work with.
Content quality. Strong sales and good reviews suggest a quality book, but the score doesn’t assess the writing itself. Check the sample.
Competition. The score doesn’t know how many other narrators are already pursuing the same title. This is where timing and speed matter, another reason to check in regularly.
The Score Is Alive
Sleuthy recalculates Lead Scores regularly as it refreshes book data. A title’s score can change over time as its sales rank shifts, new reviews come in, or data is updated. A book that was amber last month might be green today, or vice versa. The database is a living thing.
Use the score as your compass, but let your own expertise be the map. Happy prospecting!