Awhile back, I found myself browsing the Forge World website and lamenting the disappearance of a number of models that, while not officially discontinued, have been out of stock on the old website, and gone from the new one. The standard explanation for that is that the moulds are in dire need of work and “other priorities” are taking precedence – presumably their Horus Heresy line, which as far as anyone can tell is a license to print money.

Which raises the question: Has the Horus Heresy slowed down the release schedule for 40K related projects?

Trying to find that out for models would be difficult, and involve a great deal of scraping the Forge World website for a long time as things go in and out of stock and well…it’s not going to happen. Books on the other hand, have solid release dates, and presumably suffer from some of the same problems of too many projects and too few resources.

So…has Horus Heresy slowed down Imperial Armour products?

I’m looking at this using something called time-to-event analysis, which does basically what the name suggests – it attempts to measure the time it takes for a particular event to happen. In this case, the time between one book release and the next.

Lets take a look at all the books Forge World has released as a whole. This dataset ignores the first Imperial Armour book and the first Horus Heresy book because these don’t have a meaningful predecessor. I’m also ignoring the updates, which are updates, and which were absurdly hard to find publication dates for. The publication date, by month, is pulled from Lexicanum, Amazon.com release dates, or mentions in the 40K press from places like BoLS, in general order of how I searched for them.

The plot above is what’s called a survival curve (or a Kaplan-Meier survival curve to be exact). Basically, this plots out the distribution of times from one book release to the next. Drawing a line from the y-axis to the red line, and then down to the x-axis tells you what proportion of books had a release interval of that time or sooner. For example, starting at 0.50 (or 50% of books), we go down to 6 months, indicating that about half of all Forge World books came out 6 months or less after the previous book. The dotted grey lines are a 95% confidence interval, which can largely be ignored here for both practical and theoretical reasons.

What’s interesting is that there’s a fairly steady cadence of release times between 0 and 15 months, and then a very long tail, with a small number of books having an interval between releases of greater than two years. Those books are very early in the history of Imperial Armour.

Now, lets look at a couple ways to break up the data to try to get at our question about whether or not Horus Heresy is slowing everything up.

Now we look at the release curves for Imperial Armour (red) vs. Horus Heresy (blue). The red curve is largely as we previously described. Horus Heresy has a much more distinctive curve – there’s no releases that take shorter than 6 months, and none that take more than 12. It is, for an admittedly small number of releases, quite predictable, with neither ultra-long waits between releases, but also no extremely short turnaround books (the Apocalypse books often come out very frequently after another IA book). So while HH books have a very reliable cadence, the majority of Imperial Armour books actually come out closer on the heels of a previous release than their Horus Heresy brethren.

But that just addresses whether or not Horus Heresy books come out faster than IA books. What about IA books written in the era after Horus Heresy started? Have those been slower?

The answer to this, looking only at Imperial Armour books, is a resounding no. The much steeper slope of the blue curve, which is those books that were written after the Horus Heresy’s initial release, indicates a much more aggressive release schedule, with no book even waiting 10 months before a successor is published.

So the answer is a resounding No, at least as far as book publishing is concerned. Any slowdown due to dividing resources between the Horus Heresy and Imperial Armour has been offset by Forge World coming into its own, and dramatically increasing their release cadence. So while those of us not participating in the Heresy might be a little disappointed by the prominence of the line, Forge World’s releases have gotten better for everyone.

Now, there is one caveat to this analysis: Many of the books released after the Horus Heresy began are second editions of older books, which presumably require less effort. However, I’m including these as a positive note because, in my experience, there’s nothing more frustrating than having an out-of-date book, and many of these updates have been quite substantial in their revisions (I’m thinking particular of the Space Marine’s 2nd Edition) or been made considerably more accessible (the new single-volume Siege of Vraks).

While I was at it, I wanted to look at one more question – are linked books, like the Badab War or the original Siege of Vraks, apt to come out sooner than two unrelated books?

This one genuinely surprised me. I had assumed that, given someone was already on a project, and presumably “in the zone” in terms of writing, that linked books would come out much sooner than their independent brethren. But between not having easy targets like the Apocalypse books, and being fairly substantial releases with new model lines, these larger linked campaign books actually take longer to come out, as a group, than single-shot books.

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