Evaluation and Calculation: Heroes on that mission

How do we decide whether a ship is strong or weak? In this series of article, I'll describe how I evaluate ships. The goal is to keep things as non-technical as possible and focus on tips you can use to help you evaluate ships.

Since my Ship Efficiency Model is a reflection of how I evaluate ships, these articles will also explain how it works and what it looks at. You can always find the latest version linked at the beginning of this page.

Evaluation and Calculation series index:
- What is best in X-Wing? (1v1 effectiveness)
- Heroes on that mission (Focus fire effectiveness)
- Gains from trade (Efficiency)
- It's time for action (Actions)
- Stayin' alive (Durability)
- Dealing the damages (Damage)
- Dial me up (Maneuver dials and firing arcs)
- If you can dodge a wrench... (Arc-dodging)

There were heroes on that mission

According to TV Tropes, the first principle of Mook Chivalry is to attack one at a time (disclaimer: I claim no responsibility for any time lost to that website). Unfortunately, chivalry is dead in Star Wars. Once a swarm gets all their guns on target and someone misreads Crossfire Formation as Deadman's Switch, action heroes quickly turn into dead heroes.

In the last article, we talked about rating ships in a 1v1. Isolated matchups happen in X-Wing, so we do want to rate ships in these scenarios. However, we also need to rate ships in the far more common situations where multiple ships are shooting on the same turn. Two 3-attack ships with 4 health each is roughly a fair matchup for one 3-attack ship with 8 health if they attack one at a time. If they attack at the same time, the two 4-health ships deals about 50% more damage than the single 8-health ship!

This leads us to a common guideline for list-building:

• For the same points, adding a second copy of a ship is better than doubling the effectiveness of the first ship.

Of course, this rule of thumb conflicts with some earlier ones. You want to put good upgrades on strong ships that already survive a long time and dish out good damage, but upgrading one ship gets less and less effective in focus-fire situations. Play-testing or a math model can help you figure out when it's best to stack a ship with upgrades and when it's better to spend your points on more ships.

Lanchester's Square Law

To deal with this issue, we need to do something to the effectiveness formula so multiple small ships are rated better than one big ship with the same total health. We can do that by shrinking the value of big ships more than the value of small ships.

Normally, I'd reach into my bag of math tools and pick a well-known function that shrinks big numbers more than small numbers. In this case, someone has done the hard work and found exactly what function to use! If we had a really large number of ships that can focus fire each other, Lanchester's Square Law tells us to take the square root of their 1v1 effectiveness to get their effectiveness in focus-fire situations. Through simulation, MajorJuggler found that the small number of ships in X-Wing means we shouldn't quite take the square root, we take the 1.85th root instead (shrinks numbers less than the square root does, but it's pretty close).

Taking the nth root is the same as raising to the exponent 1/n, so if you look in the spreadsheet, you'll see something like this equation:

If you're not familiar with square roots or exponents, the important thing to remember is we're shrinking big numbers more than small numbers. Here's what the 1.85th root looks like. If we plug in 1, it stays the same. Plugging in 4 (3 higher than the previous number) gets us a number slightly larger than 2, and we have to plug in 9 (5 higher than the previous number) to get a number slightly larger than 3. The larger the number we plug in, the more it gets shrunk.

It's dangerous to go alone!

You can't have focus fire without having multiple ships, and multiple ships introduces a limitation of the effectiveness model. Our measure of ship effectiveness is pretty good when the squad is just multiple copies of the same ship. It's less reliable when some of the ships are tankier or more fragile than others.

Here's some more guidelines:

• It's not ideal to mix tanky ships with glass cannon ships in the same list.
• Generally, you want to kill your opponent's glass cannon ships first and leave their tanky ships for the end.

Sloane swarms are a great examples of lists which take advantage of these guidelines. TIE Interceptors and TIE Strikers are on the glass-cannon end of the spectrum, while ships that carry Sloane are normally tanks. However, Sloane is a powerful offensive support ability that flips its carrier's profile toward offense, and as such, all the ships in the Sloane swarm have similar offense-to-durability profiles.

Stay tuned!

We've learned about how to think about a ship's effectiveness, but that's only half of what's needed to evaluate ships. Since X-Wing is a game with a points budget, we also care about the ship's point cost. In the next article, we'll talk about point costs and efficiency and how to evaluate ships and upgrades.