Deceptive Attack solutions

[RyanW]

Did some math and came up with the best case of when/how much to use deceptive attack to get the maximum odds of getting a telling hit (successful attack and failed defense). This assumes you are counting telling hits as a success and everything else as a failure (giving no value to, for example, forcing an opponent to burn a defense or retreat, and no additional value to critical hits, aside from loss of defense). It also assumes defenses in the fairly normal range (specifically 5-16). If anyone is interested, I could extend the tables for much higher defenses.

First, find your effective skill after all modifiers except Deceptive Attack. Take enough Deceptive Attack penalty to lower it to 16 or 17 if it is higher. Now estimate the opponent's defense, taking into account all modifiers (including any Deceptive Attack you took to lower skill to 16/17).

If your effective skill is now...
...17, take a -2 penalty if estimated defense is 6-9, -4 penalty if estimated defense is 10-13, and -6 penalty if estimated defense is 14+.

...16, take a -2 penalty if estimated defense is 8-10, -4 penalty if estimated defense is 11-14, and -6 penalty if estimated defense is 15+.

...15, take a -2 penalty if estimated defense is 9-12, and -4 penalty if estimated defense is 13+.

...14, take a -2 penalty if estimated defense is 10-13, and -4 penalty if estimated defense is 14+.

...13, take a -2 penalty if estimated defense is 12+.

...12, take a -2 penalty if estimated defense is 13+.

[sir_pudding]

Are you taking the expanded Critical Hit range into account at Skill 15+? Remember, if you crit they have no defense at all!

[RyanW]

Originally Posted by sir_pudding

Are you taking the expanded Critical Hit range into account at Skill 15+? Remember, if you crit they have no defense at all!

Yes, I am. And that's what I meant by "no additional value to critical hits, aside from loss of defense." I'm counting that they don't get a defense, but giving no extra weight to critical hits due to potential effects of the critical hit table.

[Anthony]

One error: in the case of extremely high defenses, you don't want to use deceptive attack at all, just swing for crits (this is more likely for NPCs attacking PCs than the reverse). The threshold for that is normally a defense of 17+ -- 18+ if your effective skill is 14, 16+ if your effective skill is 16.

I wrote a program to get hit odds a while back. Incoming wall of data (* indicates it's the optimal choice, numbers are net hit chance).

Skill     Defense    0         1         2         3         
10        6         *0.455     0.248     0.091     0.018    
10        7         *0.422     0.237     0.089     0.018    
10        8         *0.375     0.220     0.086     0.018    
10        9         *0.319     0.197     0.081     0.017    
10        10        *0.259     0.169     0.073     0.016    
10        11        *0.199     0.139     0.065     0.015    
10        12        *0.143     0.109     0.056     0.013    
10        13        *0.097     0.081     0.046     0.012    
10        14        *0.063     0.058     0.038     0.010    
10        15        *0.041     0.041     0.031     0.008    
10        16         0.027    *0.030     0.025     0.007    
10        17        *0.027     0.023     0.022     0.006    
10        18        *0.027     0.023     0.020     0.005    
11        6         *0.569     0.358     0.159     0.046    
11        7         *0.527     0.342     0.155     0.046    
11        8         *0.468     0.317     0.149     0.045    
11        9         *0.398     0.283     0.139     0.044    
11        10        *0.322     0.241     0.125     0.042    
11        11        *0.246     0.197     0.108     0.039    
11        12        *0.176     0.152     0.090     0.036    
11        13        *0.117     0.111     0.072     0.032    
11        14         0.075    *0.076     0.056     0.029    
11        15         0.047    *0.052     0.042     0.026    
11        16         0.030    *0.035     0.032     0.023    
11        17        *0.030     0.025     0.025     0.021    
11        18        *0.030     0.025     0.021     0.020    
12        6         *0.674     0.478     0.255     0.091    
12        7         *0.624     0.455     0.248     0.091    
12        8         *0.553     0.422     0.237     0.089    
12        9         *0.470     0.375     0.220     0.086    
12        10        *0.380     0.319     0.197     0.081    
12        11        *0.289     0.259     0.169     0.073    
12        12        *0.206     0.199     0.139     0.065    
12        13         0.136    *0.143     0.109     0.056    
12        14         0.085    *0.097     0.081     0.046    
12        15         0.052    *0.063     0.058     0.038    
12        16         0.032    *0.041     0.041     0.031    
12        17        *0.032     0.027     0.030     0.025    
12        18        *0.032     0.027     0.023     0.022    
13        6         *0.762     0.597     0.368     0.159    
13        7         *0.705     0.569     0.358     0.159    
13        8         *0.626     0.527     0.342     0.155    
13        9         *0.531     0.468     0.317     0.149    
13        10        *0.428     0.398     0.283     0.139    
13        11        *0.326     0.322     0.241     0.125    
13        12         0.231    *0.246     0.197     0.108    
13        13         0.151    *0.176     0.152     0.090    
13        14         0.094    *0.117     0.111     0.072    
13        15         0.056     0.075    *0.076     0.056    
13        16         0.034     0.047    *0.052     0.042    
13        17         0.034     0.030    *0.035     0.032    
13        18        *0.034     0.030     0.025     0.025    
14        6         *0.825     0.707     0.491     0.255    
14        7         *0.763     0.674     0.478     0.255    
14        8         *0.677     0.624     0.455     0.248    
14        9         *0.574     0.553     0.422     0.237    
14        10         0.463    *0.470     0.375     0.220    
14        11         0.352    *0.380     0.319     0.197    
14        12         0.249    *0.289     0.259     0.169    
14        13         0.163    *0.206     0.199     0.139    
14        14         0.101     0.136    *0.143     0.109    
14        15         0.060     0.085    *0.097     0.081    
14        16         0.035     0.052    *0.063     0.058    
14        17         0.035     0.032    *0.041     0.041    
14        18        *0.035     0.032     0.027     0.030    
15        6         *0.870     0.800     0.614     0.368    
15        7         *0.807     0.762     0.597     0.368    
15        8         *0.718     0.705     0.569     0.358    
15        9          0.613    *0.626     0.527     0.342    
15        10         0.500    *0.531     0.468     0.317    
15        11         0.387    *0.428     0.398     0.283    
15        12         0.282    *0.326     0.322     0.241    
15        13         0.193     0.231    *0.246     0.197    
15        14         0.130     0.151    *0.176     0.152    
15        15         0.088     0.094    *0.117     0.111    
15        16         0.063     0.056     0.075    *0.076    
15        17        *0.063     0.034     0.047     0.052    
15        18        *0.063     0.034     0.030     0.035    
16        6         *0.899     0.866     0.727     0.491    
16        7         *0.837     0.825     0.707     0.491    
16        8          0.751    *0.763     0.674     0.478    
16        9          0.648    *0.677     0.624     0.455    
16        10         0.537    *0.574     0.553     0.422    
16        11         0.426     0.463    *0.470     0.375    
16        12         0.323     0.352    *0.380     0.319    
16        13         0.237     0.249    *0.289     0.259    
16        14         0.175     0.163    *0.206     0.199    
16        15         0.134     0.101     0.136    *0.143    
16        16        *0.109     0.060     0.085     0.097    
16        17        *0.109     0.035     0.052     0.063    
16        18        *0.109     0.035     0.032     0.041    
17        6          0.899    *0.912     0.823     0.614    
17        7          0.837    *0.870     0.800     0.614    
17        8          0.751    *0.807     0.762     0.597    
17        9          0.648    *0.718     0.705     0.569    
17        10         0.537     0.613    *0.626     0.527    
17        11         0.426     0.500    *0.531     0.468    
17        12         0.323     0.387    *0.428     0.398    
17        13         0.237     0.282    *0.326     0.322    
17        14         0.175     0.193     0.231    *0.246    
17        15         0.134     0.130     0.151    *0.176    
17        16         0.109     0.088     0.094    *0.117    
17        17        *0.109     0.063     0.056     0.075    
17        18        *0.109     0.063     0.034     0.047

Oh, and at a certain point rapid strike is better. At skill 22 vs defense 17, rather than using deceptive attack 6 (DA3 to reduce to 16 vs 14, then another DA3; 20.6% hit probability), rapid strike with no deceptive attack gives a 10.9% chance per shot, or an average of 0.218 hits. It's even better if the target relies on parry or block, since subsequent rolls are worse, and if you're at two on one it may be worth using rapid strike even at an effective skill of 18 or so, just to create a bigger penalty on defenses against your ally's hits.

[RyanW]

Originally Posted by Anthony

One error: in the case of extremely high defenses, you don't want to use deceptive attack at all, just swing for crits (this is more likely for NPCs attacking PCs than the reverse). The threshold for that is normally a defense of 17+ -- 18+ if your effective skill is 14, 16+ if your effective skill is 16.

I wasn't taking into account defenses over 16 (I play low/mid powered games most often, so my initial table didn't go above 16 defense). My rough table did show the skill 16 vs. defense 16 drop off, though. It just got lost somehow in the change to a more human readable format. I hadn't taken into account Rapid Strike at all, though. It's worth a look.

[NineDaysDead]

This may be of interest to you; Deceptive Attack speadsheet by seasong:

Originally Posted by seasong

Spreadsheet love:
Deceptive Attack

Enter any two attack and defense rolls and it will calculate the probabilities for up to twenty levels of Deceptive Attack (my science fiction campaign sometimes hits 30+ effective skill rolls), and also explicitly point out the optimal number of Deceptive Attack levels.

Most of the actual process is in the hidden columns, if you want to look at the specifics - I hide them to keep things visually uncomplicated.

[Grouchy Chris]

I did a bunch of number crunching on this and the simplest rule I came up with was this: when using Deceptive Attack, try to get the sum of your attack and your opponent's defense into the range 22-24. That works for a broad range of values.

[Vynticator]

Do you guys tend to play in games where you know exactly your opponent's defence scores? Just curious-we've always played 'closed data' games where you don't know enemy stats (or even fellow PC stats unless you peek!).

[Sabaron]

It's usually pretty easy to guess someone's defense scores. A rough estimate at least.

[Peter V. Dell'Orto]

Originally Posted by Sabaron

It's usually pretty easy to guess someone's defense scores. A rough estimate at least.

It's going to pretty rough if you never see their dice. I roll all NPC defenses behind my GM screen, for example, and only announce success or failure. I don't announce margin of success or failure, only observable results (you hit, he dodges, you hit his shield squarely). Even on a contest of skills, I just tell you the net result (You make it by 10, I'll say, okay, he's at -5 next turn, not that I rolled a 9 against his 14.) You end up getting only a very rough idea.

Even that kind of guessing only works well when they are recurring generic types than if they are unique NPCs.

These things more than anything else are probably why my players tend to err on the "keep your score 16+" side instead of "maximize the effects of Deceptive Attack," because I conceal enough data points to make the guesses too rough for precise gauging. Even so, I've suggested that it's worthy grouping Deceptive Attack into broad categories - if you think the foe's defenses are low, medium, or high, you should do X, Y, or Z whenever possible.