Skip to content

Commit db013d4

Browse files
committed
Tweak the advantage post a bit
1 parent 2493172 commit db013d4

4 files changed

+18
-14
lines changed

blog/archive.html

+1-1
Original file line numberDiff line numberDiff line change
@@ -53,7 +53,7 @@ <h1 style="display: none;">Lab notes</h1>
5353
<p>But what if you roll the die <strong>two</strong> times and then pick either the higher or the lower number?
5454
This is called respectively an <strong>advantage</strong> and <strong>disadvantage</strong> in D&amp;D.
5555
It feels that the effects of advantage and disadvantage on the chance of success should be similar.
56-
Yet, it couldn’t be further from the truth!<a href="#fn1" class="footnote-ref" id="fnref1" role="doc-noteref"><sup>1</sup></a></p>
56+
Yet, it couldn’t be further from the truth!</p>
5757
<!-- <video controls src="/images/posts/advantage/ProbAll.mp4" -->
5858
<!-- poster="/images/posts/advantage/ProbAll.png"/> -->
5959
</div>

blog/index.html

+1-1
Original file line numberDiff line numberDiff line change
@@ -52,7 +52,7 @@ <h1 style="display: none;">Lab notes</h1>
5252
<p>But what if you roll the die <strong>two</strong> times and then pick either the higher or the lower number?
5353
This is called respectively an <strong>advantage</strong> and <strong>disadvantage</strong> in D&amp;D.
5454
It feels that the effects of advantage and disadvantage on the chance of success should be similar.
55-
Yet, it couldn’t be further from the truth!<a href="#fn1" class="footnote-ref" id="fnref1" role="doc-noteref"><sup>1</sup></a></p>
55+
Yet, it couldn’t be further from the truth!</p>
5656
<!-- <video controls src="/images/posts/advantage/ProbAll.mp4" -->
5757
<!-- poster="/images/posts/advantage/ProbAll.png"/> -->
5858
</div>

blog/posts/2024-01-07-advantage-and-disadvantage.html

+10-8
Original file line numberDiff line numberDiff line change
@@ -53,7 +53,7 @@ <h1>Advantage and disadvantage</h1>
5353
<p>But what if you roll the die <strong>two</strong> times and then pick either the higher or the lower number?
5454
This is called respectively an <strong>advantage</strong> and <strong>disadvantage</strong> in D&amp;D.
5555
It feels that the effects of advantage and disadvantage on the chance of success should be similar.
56-
Yet, it couldn’t be further from the truth!<a href="#fn1" class="footnote-ref" id="fnref1" role="doc-noteref"><sup>1</sup></a></p>
56+
Yet, it couldn’t be further from the truth!</p>
5757
<!-- <video controls src="/images/posts/advantage/ProbAll.mp4" -->
5858
<!-- poster="/images/posts/advantage/ProbAll.png"/> -->
5959
<!--more-->
@@ -64,7 +64,7 @@ <h2 id="probabilities">Probabilities</h2>
6464
<p><span class="math display">\[
6565
\mathbb{P}(\mathrm{success})_\mathrm{adv} = 1 - (1 - p)^2 = 2p - p^2
6666
\]</span></p>
67-
<p>Since <span class="math inline">\(2p \geq p^2\)</span> when <span class="math inline">\(p \in [0,1]\)</span>, you get a nice boost to your chance of success.
67+
<p>Since <span class="math inline">\(p \geq p^2\)</span> when <span class="math inline">\(p \in [0,1]\)</span>, you get a nice boost to your chance of success compared to the one-shot probability <span class="math inline">\(p\)</span>.
6868
This can be illustrated with the following chart:</p>
6969
<video playsinline controls src="../images/posts/advantage/Prob2.mp4" poster="../images/posts/advantage/Prob2.png"></video>
7070
<p>Finally, when it comes to <strong>disadvantage</strong>, you succeed only when you succeed both your one-shot checks which gives us:</p>
@@ -75,7 +75,7 @@ <h2 id="probabilities">Probabilities</h2>
7575
<p>The charts for <strong>advantage</strong> and <strong>disadvantage</strong> look <em>somewhat</em> symmetrical.
7676
What the fuss is about?</p>
7777
<h2 id="relative-effect">Relative effect</h2>
78-
<p>Things start to get interesting when we look at the <em>relative</em> effects of advantage and disadvantage<a href="#fn2" class="footnote-ref" id="fnref2" role="doc-noteref"><sup>2</sup></a>.</p>
78+
<p>Things start to get interesting when we look at the <em>relative</em> effects of advantage and disadvantage<a href="#fn1" class="footnote-ref" id="fnref1" role="doc-noteref"><sup>1</sup></a>.</p>
7979
<p>First, let’s look at the change in the chance of success relative to the <em>one-shot</em> chance of success:</p>
8080
<p><span class="math display">\[
8181
\mathbb{P}(\mathrm{success})_\mathrm{adv} / p = 2 - p
@@ -92,14 +92,16 @@ <h2 id="relative-effect">Relative effect</h2>
9292
<p>Plotting these charts side-by-side, there’s much less symmetry than originally anticipated:</p>
9393
<video playsinline controls src="../images/posts/advantage/ProbUpDownSide.mp4" poster="../images/posts/advantage/ProbUpDownSide.png"></video>
9494
<h2 id="conclusion">Conclusion</h2>
95-
<p>In the best/worst-case scenario, when a one-shot chance of success is <span class="math inline">\(1\)</span> out of <span class="math inline">\(20\)</span>, having <strong>advantage</strong> would <em>almost</em> double your chances, but with <strong>disadvantage</strong> you’d be <span class="math inline">\(20\)</span> times less likely to succeed!</p>
96-
<p>This is an interesting asymmetry in what — at first glance — supposed to be symmetric game mechanics.
97-
I’m not sure if it’s particularly useful outside of the world of Dungeons &amp; Dragons, but the next time I play Baldur’s Gate 3, I’ll be more serious about picking <em>disadvantage</em>-inducing spells to debuff enemies rather than just throwing fireballs at them.</p>
95+
<p>In the best/worst-case scenario, when a one-shot chance of success is <span class="math inline">\(1\)</span> out of <span class="math inline">\(20\)</span>, having <strong>advantage</strong> would <em>almost</em> double your chances, but with <strong>disadvantage</strong> you’d be <span class="math inline">\(20\)</span> times less likely to succeed!
96+
Overall, <strong>disadvantage</strong> has a disproportionally large impact on the odds of success compared to the effect of <strong>advantage</strong>.
97+
This is true for the whole range of one-shot probabilities <span class="math inline">\(p \in (0, 1)\)</span>, with the gap becoming visible at <span class="math inline">\(p\)</span> around <span class="math inline">\(\frac{3}{4}\)</span> and apparent at <span class="math inline">\(p \leq \frac{1}{2}\)</span>.</p>
98+
<p>This is an interesting asymmetry in what — at first glance — supposed to be a symmetric game mechanics.
99+
I’m not sure if it’s particularly useful outside of the world of Dungeons &amp; Dragons, but the next time I play Baldur’s Gate 3, I’ll be more serious about picking <em>disadvantage</em>-inducing spells to debuff enemies rather than just throwing fireballs at them.<a href="#fn2" class="footnote-ref" id="fnref2" role="doc-noteref"><sup>2</sup></a></p>
98100
<section id="footnotes" class="footnotes footnotes-end-of-document" role="doc-endnotes">
99101
<hr />
100102
<ol>
101-
<li id="fn1"><p>The animated charts were produced with <a href="https://github.com/3b1b/manim">manim</a> library.<a href="#fnref1" class="footnote-back" role="doc-backlink">↩︎</a></p></li>
102-
<li id="fn2"><p>Just don’t mind the case when <span class="math inline">\(p = 0\)</span> which is not particularly interesting but would complicate the formulas.<a href="#fnref2" class="footnote-back" role="doc-backlink">↩︎</a></p></li>
103+
<li id="fn1"><p>Just don’t mind the case when <span class="math inline">\(p = 0\)</span> which is not particularly interesting but would complicate the formulas.<a href="#fnref1" class="footnote-back" role="doc-backlink">↩︎</a></p></li>
104+
<li id="fn2"><p>The animated charts were produced with <a href="https://github.com/3b1b/manim">manim</a> library.<a href="#fnref2" class="footnote-back" role="doc-backlink">↩︎</a></p></li>
103105
</ol>
104106
</section>
105107
</section>

hakyll/posts/2024-01-07-advantage-and-disadvantage.md

+6-4
Original file line numberDiff line numberDiff line change
@@ -12,7 +12,7 @@ Usually, to do an **ability check** you roll a 20-sided die (`d20`), compare wha
1212
But what if you roll the die **two** times and then pick either the higher or the lower number?
1313
This is called respectively an **advantage** and **disadvantage** in D&D.
1414
It feels that the effects of advantage and disadvantage on the chance of success should be similar.
15-
Yet, it couldn't be further from the truth![^manim]
15+
Yet, it couldn't be further from the truth!
1616

1717
<!-- <video controls src="/images/posts/advantage/ProbAll.mp4" -->
1818
<!-- poster="/images/posts/advantage/ProbAll.png"/> -->
@@ -32,7 +32,7 @@ $$
3232
\mathbb{P}(\mathrm{success})_\mathrm{adv} = 1 - (1 - p)^2 = 2p - p^2
3333
$$
3434

35-
Since $2p \geq p^2$ when $p \in [0,1]$, you get a nice boost to your chance of success.
35+
Since $p \geq p^2$ when $p \in [0,1]$, you get a nice boost to your chance of success compared to the one-shot probability $p$.
3636
This can be illustrated with the following chart:
3737

3838
<video playsinline controls src="/images/posts/advantage/Prob2.mp4"
@@ -85,9 +85,11 @@ Plotting these charts side-by-side, there's much less symmetry than originally a
8585
## Conclusion
8686

8787
In the best/worst-case scenario, when a one-shot chance of success is $1$ out of $20$, having **advantage** would *almost* double your chances, but with **disadvantage** you'd be $20$ times less likely to succeed!
88+
Overall, **disadvantage** has a disproportionally large impact on the odds of success compared to the effect of **advantage**.
89+
This is true for the whole range of one-shot probabilities $p \in (0, 1)$, with the gap becoming visible at $p$ around $\frac{3}{4}$ and apparent at $p \leq \frac{1}{2}$.
8890

89-
This is an interesting asymmetry in what --- at first glance --- supposed to be symmetric game mechanics.
90-
I'm not sure if it's particularly useful outside of the world of Dungeons & Dragons, but the next time I play Baldur's Gate 3, I'll be more serious about picking *disadvantage*-inducing spells to debuff enemies rather than just throwing fireballs at them.
91+
This is an interesting asymmetry in what --- at first glance --- supposed to be a symmetric game mechanics.
92+
I'm not sure if it's particularly useful outside of the world of Dungeons & Dragons, but the next time I play Baldur's Gate 3, I'll be more serious about picking *disadvantage*-inducing spells to debuff enemies rather than just throwing fireballs at them.[^manim]
9193

9294
---
9395
---

0 commit comments

Comments
 (0)