So, now our election is over, and if one thing can be declared an uncontested winner, it's Math. Despite having his vocal detractors, Nate Silver's meticulous statistical analysis of polls produced an electoral college map that was spot on. You might not like what his results were, but you can't argue with their accuracy.
Any old-school Asimov fan could have told you that. While I doubt any of us would argue that Hari Seldon's level of psychohistorical projection is probably impossible, there is a simple truth that pure math has no bias.
Now, applying this to worldbuilding. I will fully admit that I'm more of a numbers geek than your average writer, so I will do things that would probably make most people weep at the prospect of it.
Take, for example, my latest bit of Build Process, incorporating a dimension of time into my already-complex 150-ly radius Space Opera Setting. I looked at my several hundred intelligent species*, and even knowing their technology level, I asked myself, "Yes, but who got their first? How did they expand?"
So, I start with some assumptions, some of which probably have underlying errors, but work in terms of large-scale worldbuilding as a whole. It also works in terms of applying the Guns, Germs and Steel ideas on an interstellar scale.
Assumption #1: That all intelligent species in question, in this patch of interstellar neighborhood, were all at an equivalent state of Intelligent, Pre-Civilized Hunter/Gatherer at the same time. This is a HUGE presumption, especially in terms of evolution and cosmic time. It more or less requires some form of direct Precursor Intervention, which I've included in the model. The point is, the bell is rung at 11,000 BC, and at that point, every species starts the race.
Assumption #2: All species hit certain Technology Level Benchmarks, and the time ratio for those benchmarks is consistent. These benchmarks are broad brushstrokes, and don't represent the details of how a culture gets from A to B to C, or exactly what that Tech Level might mean at any given point. But it takes into account that the journey from Pre-Civilization to Early Metalworking is a much longer one than from Late Industrial to Technological.
Now, with those two assumptions, I add in two Randomizing factors to tweak those ratios for each Alien Civilization. One broadly represents Ingenuity-- how quickly a species as a whole comes up with and enacts new ideas-- and the other represents Resources-- having the natural means on hand that enable enacting new ideas. As per the underlying thesis of the Guns, Germs & Steel Model, Resources is the bigger determining factor.
For example, for the sake of the model, I assign Humans an Ingenuity Factor and Resource factor of 1. With the Ingenuity, the range of variance is pretty minute: with one exception (a species I wanted to beat everyone else to space by a wide margin), the range of Ingenuity is between .95 and 1.05. No species is really significantly smarter than anyone else.**
Resource Factor had a much bigger range, and small changes in the range could generate much larger effects. The range was, for the most part, between 0 and 2, but for species that I wanted still in a Hunter/Gatherer phase, the RF might be well into the negatives.***
And then I generate an equation that plugs the IF and RF into the Advancement Ratio I've already created, and: Bam. I now know to the year when every alien culture breaks the FTL barrier, and where every culture is, broadly speaking, in any given year.
Now, whether or not this is really useful information for a writer to know, that's debatable. It certainly falls under the Iceberg Principle of worldbuilding: stuff the reader will never see above the surface.
*- Yes, I am a loon. We've established this.
**- Not to mention, the "Ingenuity" factor really represents several different factors that don't necessarily tie into "Intelligence", such as broad social factors that could enhance or hamper scientific advancement. But I'm not a sociologist, and the math here was complicated enough. A single number that represents all those things broadly was sufficient.
***- Which could represent a lot of things: a complete lack of domesticatible animals or crops, or a sparsity of easy-to-work metals like copper or tin, for example.