Was D&D responsible for the explosion in popularity of RPGs in the 1970s?

When I was researching the scenarios timeline I soon noticed that the number of scenarios was growing rapidly year on year. Because I found out the publication month for almost all the scenarios, we can clearly see this by plotting a cumulative graph of scenarios by date:

Because of this raw data we can dig into some fundamental questions about D&D without relying upon perceived wisdom or looking through the distorted lens of expectations. Looking closer at the data I realised that the near universal perception that RPGS are popular because of D&D is infact the wrong way round - RPGs would have become popular without the publication of D&D - instead the place of D&D would have been taken by something else which had been seeded from Blackmoor.

To see this we have to look more closely at the data. I observed in my timeline posts that throughout the 1970s the number of scenarios was roughly doubling every year – exponential growth – and the way to verify this is to do a log plot and see if the result is a straight line:

That’s an astonishingly close match to a straight line. It doubles 8 times in 8½ years, and it does this at a very consistent rate. At some point the growth must have slowed down, else we'd be up to 96 trillion scenarios by now - 12,000 for every person on the planet!

Inferring Growth in RPG Popularity

Now my data is all about scenarios, not about RPG publications in general, or rule-sets in particular, or numbers of players – and data for these is harder or impossible to obtain - but it is reasonable to assume that these were also following a consistent exponential growth, but at a different rate (steeper for number of players, less-steep for rule sets).

If that is the case, then at any point in the 70s a majority of the then-current players of the game had taken it up in the last year, and also to anyone who started playing the game it would appear that RPGs only really started to take off in popularity at the point they took it up. This would explain why there are annecdotally so many different “D&D really took off in popularity after” events

For example, from Medium.com on a discussion of the development of the first computer RPGs, "D&D didn’t really explode in popularity until August 1974 at Gen Con, held in the same Midwest region where the PLATO authors lived."

From warpstoneptune on the publication of the AD&D coloring book we have "It was a lucky hunch to publish AD&D. Shortly after its release a Michigan State student mysteriously disappeared. The only clues to his whereabouts were some odd symbols scratched on a classroom blackboard—symbols particular to the D&D game. The cryptic clues were all the news media need to flash the story—and the game—from coast to coast. The student reappeared a few days after vanishing, and headlines turned elsewhere—but not before putting the game on the map and helping to make a super seller for Troubador."

There is no point at which the angle of the slope changes – the first Gen Con, the start of Dragon Magazine, the first TSR modules, the James Dallas Egbert case – nothing affects the growth rate set right at the start. There are places where the curve lags behind, and where it moves ahead, so any momentary lull or surge is then compensated for shortly afterwards.

Hence I suggest that the events thought to have driven the popularity of D&D were infact an inevitable byproduct of the unstoppable increasing popularity of RPGs - not the other way round.

The D&D Ruleset - Cause or Effect

Since I'm claiming that cause and effect here are the reverse of people's perception - that the increase in popularity cannot be ascribed to specific events, but that the increase in popularity was inevitable and thus these events were bound to occur at some point along the line of increasing popularity - then one core event needs to be examined.

Of the first 10 scenarios in the timeline published in the first 4 years of RPGs, six of them are Blackmoor, or derived from Blackmoor without any knowledge of the published game D&D. They actually use four different rule sets over this period – the informal Blackmoor Rules, Dungeon!, "Minneapolis Dungeon" (also known as "Castle Keep" and published as "The Rules to the Game of Dungeon"), as well as D&D. These rulesets are all related, but they are not the same game – and in particular Blackmoor was not D&D. That is, from the very start Blackmoor had inspired multiple competing systems, and it would clearly have continued to do so even if D&D had never been published.

To see the effect of the publication of D&D let's discard these first 10 scenarios - all the data we have before Jan 1975 - and using a line of best fit extrapolate backwards four years to a probable inception date. This gives an estimated date for the creation of Blackmoor Dungeon as 17th March 1971 – only a couple of months out:

This means that it appears neither the invention of D&D, nor it's publication, appear to have affected the inexorable rise of Dungeon-crawls / RPGs.

This leads me to conclude that instead of the exponential popularity of Dungeon-crawls / RPGs being due to the publication of D&D – it was instead the other way round - the exponential growth of Dungeon-crawls / RPGs meant that widespread publication of a set of rules for such a game was inevitable. That is, if Gary had not heard about Blackmoor and turned it into D&D, it would still have turned into a phenomenon, just a differently flavoured one to the one we know. Blackmoor had already spawned an as-yet-unpublished boardgame Dungeon! and an as-yet-unpublished RPG The Game of Dungeon, and without D&D this process of germination would have continued until finally it produced a published set of game rules that conquered the world - this game concept was going to expand and escape somehow.

This doesn't of course explain the long-term popularity of D&D - and if I doubt that its current pre-eminence is primarily due to it being the first published RPG ruleset (a common viewpoint) then that means I believe it has some other properties that lead to its longevity. Dungeon! did not retain its place as the pre-eminent Dungeoncrawl, nor did Blackmoor or Greyhawk retain their place as the pre-eminent setting - even TSR did not remain #1 publisher. So, despite its detractors, there is something else about D&D that put it where it is today.