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Extending the Task Resolution System to D20 Traveller

This article originally appeared on the pre-magazine Freelance Traveller website in 2003, and was reprinted in the November/December 2015 issue.

Open Game Content Note

Material appearing in a box like this is to be considered Open Game Content governed by the Open Game License.


In June of 1999, BITS (British Isles Traveller Support) (http://www.bitsuk.net/) published a set of writer’s guidelines for their generic Traveller adventures. In order to make their modules compatible with as many products as possible, BITS used a generic task resolution system that worked with Classic Traveller (CT), MegaTraveller (MT), Traveller: The New Era (TNE), Marc Miller’s Traveller (T4), and GURPS Traveller (GT). This generic task system can still be found as a download on BITS’ website, http://www.bitsuk.net/Archive/GameAids/files/BITSTaskSystem.pdf

The release of Traveller20 (D20 Traveller, also called T20), which implemented the D20 System as its core game mechanic, drifted away from the concept of prior Traveller task systems. The skill check difficulty classes (DCs) seemed erratic, some being too easy and others being too difficult. Moreover, these DCs generally defied easy categorization, particularly in those areas of the rules that were not carried over from the D20 System. Until the referee gets used to the system and memorizes the haphazard skill DCs, he finds himself constantly referencing the rules, which slows down game play.

This article presents a means of extending a task resolution system into T20. The reasons for this are twofold: First, the use of universal difficulty descriptors allows the referee to easily produce reliable and consistent skill check DCs with a minimum of rulebook references, thus speeding play. Second, a number of excellent adventures have been released in previous versions of Traveller, and using such a system would ease the conversion process.

Task Difficulties

In T20, characters possess skills based on skill ranks selected at each level of advancement, which can be modified by a specific ability score, synergy bonuses from other skills, and the impact of various feats such as Skill Focus. When making a skill check, T20 characters roll a d20 and add the skill ranks and modifiers, comparing the final result to a skill check DC, with is either an opposed roll or a static value. Using this task resolution system, the general difficulty of a task can be described with a Difficulty Level, a one-word verbal description of how hard it is to resolve a specific task. Each Difficulty Level refers to a specific skill check DC, a static value detailed in the Task Difficulties table that follows. (The names of the Difficulty Levels are identical to the BITS descriptors, for ease of use during conversion efforts.)


Task Difficulties
Difficulty Level Skill Check DC
Easy 10
Average 15
Difficult 20
Formidable 25
Staggering 30
Impossible 35
Hopeless 40
Opposed Set dynamically, usually by comparing the character’s skill check to the result of an opponent’s opposed skill check. A good example would be a ‘Spot’ check that is opposed by the opponent’s ‘Hide’ check.

Spectacular Results

Task resolution typically defines the failure or success of a task. Sometimes, however, there are added benefits when a character succeeds incredibly well. Likewise, situations exist where a dismal failure produces results far worse than a simple failure might. In order to reflect either of these types of scenarios, there must be a means of defining spectacular results.

Spectacular Success:
When a character succeeds in a skill check by a margin of ten or more, the character is assumed to have made a Spectacular Success, and may receive some additional benefit as a result of that roll.
Spectacular Failure:
When a character fails a skill check by a margin of ten or more, the character is assumed to have made a Spectacular Failure, and may receive some additional penalty as a result of this failure.

Modifying the Difficulty Level

A number of circumstances can modify the Difficulty Level of a task. While performing brain surgery is admittedly a Formidable task normally, certain conditions can improve or decrease a character’s chance at success.

Performing a task under fire:
Performing a task in a dangerous situation, such as in the midst of combat, typically increases the Difficulty Level of a task by sometimes one or usually two levels, making it significantly more difficult to perform. (For example, brain surgery is considerably harder in the midst of a gunfight as opposed to in a quiet surgical theater.)
Inappropriate location:
Performing a task in an inappropriate location, such as making repairs in the field, can increase a task’s difficulty by one level.
Lack of proper tools:
Performing a task without the proper tools can increase a task’s difficulty by one level. Some tasks can be performed without tools at all, while others require at least makeshift tools.
Lack of spare parts:
Performing a task without the proper spare parts available, forcing one to improvise using inappropriate materials, can increase a task’s difficulty by one level.
Crossing racial lines:
When performing a task that would become more difficulty when working on other races or species, such as attempting to perform a medical diagnosis on an alien species for which you have not been trained, increase a task’s difficulty by one level.
Using inappropriate technology:
Some skills, particular Technical skills, are often dependent on the Tech Level at which they were mastered. Technology that is more advanced than the character’s training is all theoretical to the character, at best. By the same token, the more advanced one becomes, the more dependent one becomes on technology, so the more primitive equipment is less likely to be of use to the trained professional. To reflect that tendency, the following rules apply on tasks that require the use of technological implements:
  • When dealing with technology more advanced than the character’s level of mastery, the task’s Difficulty Level increase by one level per tech level higher than the character’s mastery, due to the lack of understanding advanced technology.
  • When dealing with technology less advanced than the character’s level of mastery, the task's Difficulty Level increase by one level for every four full tech levels lower than the character’s mastery, due to the restrictions that come about from using primitive technology.
  • A character’s mastery can be determined by both the average tech level of the interstellar society to which they belong and the tech level of the character’s homeworld. This should be determined by the referee based on the needs of the campaign. In the event that the character has training at various tech levels, the referee should use whichever is most advantageous to the character performing the task.
  • In any event, if a task can be performed without the use of technology at all, the maximum increase in difficulty is one level, since a professional would most likely attempt the task barehanded rather than use tools that hinder more than doing it by hand.
Working with the Law:
Tasks that are impacted by local law levels are often defined by their difficulty in a lawless (Law Level 0) or Low law level (1-3) society. In the event that the tasks are more difficult at stricter law levels, increase the Difficulty Level of the task by one level for worlds of a Moderate law level (4-7), by two levels for High law level (8-9) worlds, and by three levels for Extreme law level (A+) worlds.
In situations where tasks become easier in a stricter law level (rarer, but they do exist), decrease the task’s Difficulty Level by one level for worlds of a Moderate law level (4-7), by two levels for High law level (8-9) worlds, and by three levels for Extreme law level (A+) worlds.

Additional Rules

The following are additional rules for consideration in using this task resolution system. Using these rules is not required, but doing so may improve the effective use of skills, and rewards characters that specialize.

Aiding Another:
When making a skill check to aid another, the assisting character grants a base +2 circumstance bonus for making a DC 10 on the roll, +1 to the circumstance bonus for every ten points by which the roll exceeds the base DC 10. (i.e., If the assisting character rolls a 13 on his assisting skill check, the aided character gets a +2 circumstance bonus. However, if the assisting character rolls a total of 33 on his assisting skill check, the aided character gets {+2 base, +2 for being 20+ more than the base DC 10 = +4 total} a +4 circumstance bonus.)
A character using the Leadership skill can lower the base DC for Aiding Another to a DC 5 by making a Leadership skill check at a Difficulty Level equal to the difficulty of the original task. In this case, the additional circumstance bonuses are earned for every ten points that the skill check exceeds the base DC of 5.
Alternate Difficulty Levels:
If the Referee does not desire to remain with a BITS-inspired Difficulty Level model, the Difficulty Classes table at the beginning of the Skills chapter in both T20 Lite and the Traveller’s Handbook provide an alternate set of descriptors and more levels of variation, as shown in the following table.
“Official” T20 Task Difficulties
Difficulty Level Skill Check DC BITS Equivalent
Simple 0 Easy
Very Easy 5 Easy
Easy 10 Easy
Average 15 Average
Hard 20 Difficult
Difficult 25 Formidable
Formidable 30 Staggering
Challenging 35 Impossible
Incredible 40 Hopeless
Nearly Impossible 40 Hopeless
Opposed Special, as previously
Extended Tasks:
This rule helps define tasks that occur over an extended period of time, and typically require multiple checks. Examples of such tasks include competing in a speeder race, or warming up a starship (which might take a minute or two) while a melee combat take place nearby (occuring in rounds). To resolve an extended task:
  1. Define the task’s Difficulty Level, thus setting the skill check DC.
  2. Then define the average amount of time the task will require, and determine how many checks would represent this measure of time.
  3. Multiply the number of checks by the DC based on the Difficulty Level to arrive at a target number. (Alternately, the referee could set an arbitrary target number.)
  4. Every round of action (or similar unit of time), roll a skill check and add the result to a cumulative total.
  5. The extended task is resolved when the target number is achieved.
  6. In opposed extended tasks, the first to reach the target number succeeds. If both reach the total in the same round, the one whose accumulated total is higher succeeds. If both have the same accumulated total, then the higher total skill modifier determines who succeeds. If there’s still a question, flip a coin to determine the winner or roll another opposed simple skill check, the highest result becoming the winner.
For example, assume that a starship pilot is contacted by crewmembers requesting backup in a combat situation. The pilot has to warm the ship up from its rest state, an Average task that takes about two minutes. An Average task has a skill check DC of 15, and two minutes is approximately twenty rounds of combat. From that, the referee determines that an extended task roll must reach (15 DC times twenty rounds) a total of 300. Not wanting the fight to last that long, the referee quickly drops the value to 200 before telling the players the goal. As the combat continues with the trapped characters, the pilot rolls his T/Engineering skill check every round, and adds the result of his check to a running total. When the running total equals or exceeds 200, the pilot can take the ship into the air and fly to the rescue of his comrades.
In another example, the characters are racing through the city streets in pursuit of an alien bearing a vial of virulent viruses, hoping to stop him before he can get away. The Referee determines that the chase is Difficult, and he imagines that it should be resolved in perhaps four skill checks, so he sets the target number at (DC 20 times four skill checks) 80. If the alien achieves 80 first, he gets away; if the players do, they catch up with him before he can get away. Each round of action, the two drivers roll their Drive checks as they whip through the city, and the Referee describes the action, building the suspense for the players. When one side reaches 80, the chase ends, with one of the two results.