Tuesday, February 16, 2016

Difficulty Curves and Pacing in Gaming and Instruction

The first week in GOBLIN has focused on issues related to difficulty curves and scaffolding in instructional design.  I found the discussion of difficulty curves to be the most inspiring in terms of both my thoughts on game design and instruction.  I intend to follow a simple format for most of these reaction/discussion posts on the GOBLIN program.  I will separate my general discussion from specific discussions of game design and instructional design.  I hope this will enable people to skim through the parts that don't interest them.

Difficulty Curve by David Maletz (Gamasutra)
The basic concept of a difficulty curve is relatively simple.  In games (and in academic course work), people like to experience gradually increasing difficulty -- possibly with some oscillation to introduce variability.  In World of Warcraft, this means that players are limited to specific zones including challenges appropriate to their player level.  When the player completes the content, she should be ready to progress to the next zone and the next higher cluster of challenges.  In academic courses, this means that students should steadily be able to increase their comprehension of the material.  Once they have mastered one set of concepts, they can progress to the next.  One of the best examples of this in my life has actually been my martial arts training.  The curriculum I studied was designed expertly so that material that I was sure I would never be able to learn was about as hard to learn (when I reached that point in the curriculum) as the material I was learning in the first few months.  The learning curve there was remarkably smooth.

You can find a good explanation of difficulty curves in gaming on this Gamasutra page

What has careful thought about difficulty curves meant for my approach to game design and instruction?

In RPG design:

The topic of difficulty curves is embedded in the reviews/criticisms of two recent game systems.  The most prominent is the DnD 5E system of "bounded accuracy."  The intent is to lower the advancement/power curve so that creatures can remain challenging across a broader range of character levels.  Some have criticized this as making more levels seem "same-ish" as it is less clear that players advance past some types of creatures and challenges.  If a player still feels threatened by an orc at 5th level (as they were at 1st level), he may not see enough progression to satisfy that need in the game design.  From what I can tell, this criticism is a minority opinion.  More people like the extended range of utility of threats than are put off by the potential for perceived slow advancement.  This is similar to the concern that too shallow a learning curve will bore players (or learners).

A deeper problem emerged for me some time between 3e and early 4e.  The focus on a clear difficulty curve made the game formulaic.  I started to see all monsters as carefully formulated bags of hit points with the level mandated set of abilities.  Adventures similarly became algorithmic and somewhere the magic was lost.  I have not played enough 5e to tell whether bounded accuracy resolves the problem, or not.   My experience has suggested that a little of the "magic" is back by not having as rote a method of defining difficulty or types of encounters.

A similar criticism has been leveled at the Cypher System games that I discuss more often in this blog (Numenera, The Strange, etc.).  In that system there are six "tiers" of character advancement.  The system has been subject to criticism from two sides in terms of the underlying difficulty curve.  First, some have argued that the six tier system does not allow enough to differentiate character levels.  As a result, they argue the progression curve is too shallow.  One can think of this progression curve as a simple transformation from "difficulty" to "progression is the level of difficulty one can anticipate to overcome with ease."  Ironically, the subject is also subject to criticism for making the sixth tier characters so powerful that there are almost no effective threats left to face.  Somehow, the shallow progression curve ends up to high.

The general discussion of difficulty curves have brought me back to considering the difficulty curve of The Strange -- though I reached a point of "how I learned to stop worrying and love the [ game's difficulty curve]".  It is true that in Cypher System games that high level players can overcome just about anything.  It does require that game designers (or individual game masters) present almost absurd levels of challenge -- but that is what the top tier is all about.  If that is not your game -- and it is not mine -- just don't ever get there.  Once you get to a point where the progression curve is creating a game you don't like, start over with new characters.

In many ways, the Cypher System games (Numenera and The Strange in particular) addressed the problems I had encountered with the formulaic nature of encounter design in 3/4e DnD.  The Cypher System games did not dwell on how to make the perfectly balanced encounters or a smooth difficulty curve.  There was no pretense that one group's path to tier two would be "just as hard" as some other group's path.  The use of cyphers (powerful, one-use items) and other elements of the game convinced me to ignore the careful balance of encounters and focus, instead, on telling a fun story.  If that meant that my group had a relatively easy time for several sessions - so be it.  There are mechanism built in to make individual encounters easier or harder on the fly if you get the balance wrong.  Instead of holding everyone to a specific standard of progression (difficulty) it leaves it to the GM to decide what will make for the most fun at any given time.

It took getting over careful attention to the difficulty curve of leveling to get me back into RPG gaming.

In instructional design:

My reactions to difficulty curves in instructional design is painted, to some extent, by my experience working with (and later abandoning them) in RPG design.  I see a much stronger case for attention to difficulty curves in instructional design.  For the most part, difficulty curves will likely only be obvious to students in retrospect.  I don't see the potential for alienating students by making the difficulty curve too obvious.  Instead, I have seen detailed explanations of the difficulty curve in class help me motivate students.  When I can explain how they will learn X, which will let them learn Y, which will let them learn Z, which will let them complete a final project, I often get the students' attention. This works best when I can build the progression into the syllabus and emphasize it throughout the semester.

Of course, designing a difficulty curve for a course can be quite tricky.  In my chemistry education (BS level -- before changing majors my senior year), I joked that each year involved lying to me a little less.  The difficulty curve was tested across generations where it became clear what one needed in year one vs. year three vs. graduate school, etc.  There is certainly progress in the way that the material is taught but a lot of chemistry major third year undergrads are currently working on early concepts in quantum mechanics and instrumental analysis -- just as they were 20 years ago.

In my classes in political science, there is not as clear a pathway through key knowledge and skills.  There is no consensus on which classes are essential or how to sequence knowledge.  The class I am teaching now has, as far as I can tell, pretty much no precedent in the field against which I can compare the difficulty curve.  I have compensated by making the progression through the material as clear as I can to student.  I do this with repeated call backs to previous material (now seen through the lens of later material) and assignment that clearly build on each other.

These challenges to designing difficulty curves do not make the notion less important.  If anything, I am just more convinced of the importance of the concept as a metaphor in my classes.

The next challenge is to deal with heterogeneity in the difficulty curve across the diverse students in the class -- but I don't think I am ready to tackle that yet.


  1. Great post Scott!

    Difficulty curves in games and instruction is one of my favorite concept overlaps. Games often live or die by their pacing, scaffolding, and difficulty curve design, and instruction is subject to the same principles. I agree the challenge of engaging a diverse group of students (who are all at different levels of content understanding in a course) can be tough. I think part of the solution may involve giving students more choice on assignments and how they will be assessed in their learning—exam or paper, journaling or blogging, presenting or creating instructional videos, etc.

    Keep up the awesome work!

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