Simplifying probability for Age of Sigmar

 

Probability is a huge part of Age of Sigmar, whether you look in to the finer detail of math-hammer or just like to roll the dice and get on with it understanding the probabilities will undoubtedly make you a better player. How likely is an 8" charge? Should you expect to get that spell off on a 6+ to cast? how about with a re-roll...

In this post I aim to do some of the leg work to simplify the numbers in to more memorable statements by using the "Probability Yardstick" shown below. This essentially just relates the actual percentile chance of of something occurring to a phrase that should be mentally easier to digest and consider for your plan.

For a simple example lets use a D6 roll:

• 1+ is 100% success which is "Certain"
• 2+ is 83% success which is "Highly Likely"
• 3+ is 67% success which is "Probable or Likely"
• 4+ is 50% success which is "a Realistic Possibility"
• 5+ is 34% success which is "Unlikely
• 6+ is 17% success which is "Highly Unlikely"

Now it's not hugely useful as most people understand that a 5+ or 6+ wont occur that often, however lets apply this to a 2D6 roll:

• 2+ is 100% success which is "Certain"
• 3+ is 97.2% success which is "Highly Likely"
• 4+ is 91.7% success which is "Highly Likely"
• 5+ is 83.3% success which is "Highly Likely"
• 6+ is 72.2% success which is "Probable or Likely"
• 7+ is 58.3% success which is "Probable or Likely"
• 8+ is 41.7% success which is "a Realistic Possibility"
• 9+ is 27.8% success which is "Unlikely
• 10+ is 16.7% success which is "Highly Unlikely"
• 11+ is 8.3% success which is "Highly Unlikely"
• 12 is 2.8% success which is "Remote Chance"

Additionally for the sake of miss-casts:

• Double 1 is 2.78% success which is "a Remote chance"

What you can see is that it's not a linear scale like the D6 roll, so it's not so obvious exactly where it goes from likely to unlikely. So from this it's good to plan the most important aspects of your plan on rolls that are "highly likely". Then any supporting aspects should be "Probably or Likely". 

Now an important thing to consider is re-rolls at this changes the tables significantly:

• 1+ is 100% success which is "Certain"
• 2+ is 97% success which is "Almost Certain"
• 3+ is 89% success which is "Highly Likely"
• 4+ is 75% success which is "Probable or Likely"
• 5+ is 55% success which is "Probable or Likely"
• 6+ is 31% success which is "Unlikely"

Now re-rolls on a 2D6 roll:

• 2+ is 100% success which is "Certain"
• 3+ is 99% success which is "Almost Certain"
• 4+ is 99% success which is "Almost Certain"
• 5+ is 97% success which is "Almost Certain"
• 6+ is 92% success which is "Highly Likely"
• 7+ is 83% success which is "Highly Likely"
• 8+ is 66% success which is "Probable or Likely"
• 9+ is 48% success which is "a Realistic Possibility
• 10+ is 31% success which is "Unlikely"
• 11+ is 16% success which is "Highly Unlikely"
• 12 is 5.5% success which is "Remote Chance"

What you can hopefully see is that re-rolls change the "Highly Likely" or better from a 2+ to a 3+ on a D6 roll and from a 5+ to a 7+ on a 2D6 roll. So you can adjust your plan appropriately. If you really want to get Blades of Putrefaction spell off on a 7+ as an important part of your plan you know you need a re-roll or it's not likely enough.

To use this information in your list building or cheat sheet, it's worthwhile to go through each of your faction or unit's abilities and spells etc. and label their likeliness using the tables above; make sure to include core abilities that you expect to use. This way you can get a feel for which areas you can rely on in your plan and which you should plan to have redundancies for.

As a general rule of thumb it's safe to plan using Murphy’s Law: “Whatever can go wrong, will go wrong” and to counter this there's an old military saying: "Two is one, one is none" i.e. if you need something to happen you take two. 

Should your plan revolve around anything lower than "Highly Likely" then my suggestion is to have at least two if not three of that thing i.e. if you absolutely need to charge something to gain an objective and you can't get within 5" charge range, then you should have two or ideally three units lined up to attempt the charge.

You will have to apply some lateral thinking with this and double up roles for units in your army or in your plan. A unit of Blood Knights for example could be a hammer unit and a support anvil unit for example, or during the game a lone hero that was previously supporting a unit could be a back up objective grabber.

A more abstract example is on a combat profile. A small amount of 2+ or 3+ re-roll attacks should be enough to get the damage through however on a straight 3+ or worse you will want double if not triple the attacks to ensure the damage gets through (Known in some circles as the Doombull Curse!). Obviously this is massively situational but it needs to be considered if you need to take one last wound off a hero for a battle tactic. 

So in summary these are Jabber's golden rules of defeating probability:

• Abilities that are important to your plan should be "Highly Likely" or better.
• Abilities in support of your plan should be "Probable or Likely" or better.
• Have two of anything important to your plan.
• Have three of anything in support of your plan.