Building Skill With Practice


Teaching: 20 min
Exercises: 40 min
  • How do people learn?

  • Who is a typical Carpentries learner?

  • How can we help novices become competent practitioners?

  • Compare and contrast the three stages of skill acquisition.

  • Identify a mental model and explain what it represents.

  • Explain why practice and feedback are important for learning.

  • Explain the purpose of formative assessments.

  • Identify formative assessments in your teaching and learning experiences.

We will now get started with a discussion of how learning works. We will learn some key findings from educational research and identify how these principles are put into practice in Carpentries workshops.

The Carpentries Pedagogical Model

The Carpentries aims to teach computational competence to learners. We take an applied approach, avoiding the theoretical and general in favor of the practical and specific. By showing learners how to solve specific problems with specific tools and providing hands-on practice, we develop learners’ confidence and lay the foundation for future learning.

A critical component of this process is that learners are able to practice what they are learning in real time, get feedback on what they are doing, and then apply those lessons learned to the next step in the learning process. Having learners help each other during the workshops also helps to reinforce concepts taught during the workshops.

A Carpentries workshop is an interactive event – for learners and instructors. We give and receive feedback throughout the course of a workshop. We incorporate assessments within the lesson materials and ask for feedback on sticky notes during lunch breaks and at the end of each day. In this way, instructors can adjust the pace and content of a workshop to meet the needs of the learners in that group, as well as collect feedback that will help us improve lesson materials or methodology for future workshops. Instructors and helpers also provide feedback to learners throughout workshops in order to get them unstuck or provide a greater depth of understanding about the materials. Interacting in this way with the learners helps us determine how they are doing and figure out what concepts people are having trouble with or where we might be able to move along more quickly.

The Acquisition of Skill

Our approach is based on the work of researchers like Patricia Benner, who applied the Dreyfus model of skill acquisition in her studies of how nurses progress from novice to expert (see also books by Benner). This work indicates that through practice and formal instruction, learners acquire skills and advance through distinct stages. In simplified form, the three stages of this model are:

Three people, labeled from left to right as "Novice", "Competent Practitioner", and "Expert". Underneath the people,
an arrow labelled "Experience level" points from left to right. Underneath the figure labelled "Novice" a quote says "I'm not sure what questions to ask." The Competent Practitioner says "I'm pretty confident, but I still look stuff up a lot!" The Expert says "I've been doing this on a daily basis for years!"

For now, we are primarily concerned with novices, as this tends to characterize The Carpentries audience. (We, as instructors, are more likely to be competent practitioners or experts, and we will discuss this in a later section). We will next use an additional concept to help us differentiate between novices and competent practitioners, which will have implications for how we teach novices.

Cognitive Development and Mental Models

Effective learning is facilitated by the creation of a well-founded mental model. A mental model is a collection of concepts and facts, along with the relationships between those concepts, which a person has about a topic. For example, a long-time resident of the United States may have an advanced understanding of the location of US states, major cities and landmarks, weather patterns, regional economies and demographic patterns, as well as the relationships among these, compared with their understanding of these relationships for other countries. In other words, their mental model of the United States is more complex compared with their mental model of other countries.

We can distinguish between a novice and a competent practitioner for a given domain based on the complexity of their mental models.

Three collections of six circles. The first collection is labelled "Novice" and has only two arrows connecting some of the circles. The second collection, labelled "Competent Practitioner" has six connecting arrows. The third collection, labelled "Expert", is densly connected, with eight connecting arrows.

We will discuss the mental models of experts in more detail in a later lesson.

Your Mental Models

In the Etherpad, write your primary research domain or area of expertise and some aspects of the mental model you use to frame and understand your work. What concepts/facts are included? What types of relationships are included?

This discussion should take about 5 minutes.

One key insight from research on cognitive development is that novices, competent practitioners, and experts each need to be taught differently. In particular, presenting novices with a pile of facts early on is counter-productive, because they do not yet have a model or framework to fit those facts into. In fact, presenting too many facts too soon can actually reinforce an incorrect mental model.

Most learners coming to Carpentries lessons are novices, and do not have a strong mental model of the concepts we are teaching. Thus, our primary goal is not to teach the syntax of a particular programming language, but to help them construct a working mental model so that they have something to attach facts to. In other words, our goal is to teach people how to think about programming and data management in a way that will allow them to learn more on their own or understand what they might find online.

The Importance of Going Slowly

If someone feels it is too slow, they will be a bit bored. If they feel it is too fast, they will never come back to programming. — Kunal Marwaha, SWC Instructor

If our goal is to help novices construct an accurate and useful mental model of a new intellectual domain, this will impact our teaching. For example, we principally want to help learners form the right categories and make connections among concepts. We do not want to overload them with a slew of unrelated facts, as this will be confusing.

An important practical implication of this latter point is the pace at which we teach.
In the first main episode of Software Carpentry’s lesson on the Unix shell, which covers “Navigating Files and Directories”, there are only four “commands” for 40 minutes of teaching. Ten minutes per command may seem glacially slow, but that episodes’s real purpose is to teach learners about paths; later on, they will learn about history, wildcards, pipes and filters, command-line arguments, redirection, and all the other big ideas on which the shell depends, and without which people cannot understand how to use commands.

That mental model of the shell also includes things like:

These two examples illustrate something else as well. Learning consists of more than “just” building mental models and adding information to them; creating linkages between concepts and facts is at least as important. Telling people that they should not repeat things, and that they should try to think in terms of little pieces loosely joined, both set the stage for discussing functions. Explicitly referring back to pipes and filters in the shell when introducing functions helps solidify both ideas.

Meeting Learners Where They Are

One of the strengths of Carpentries workshops is that we meet learners where they are at. Carpentries Instructors strive to help learners progress from whatever starting point they happen to be at, without making anyone feel inferior about their current practices or skillsets. We do this in part by teaching relevant and useful skills building an inclusive learning environment, and continually getting (and paying attention to!) feedback from learners. We will be talking in more depth about each of these strategies as we go forward in our workshop.

How “Knowledge” Gets in the Way

Besides going slowly, what else can we do to facilitate the formation of sufficiently accurate mental models? One important action is to address the misconceptions of broken mental models.

Mental models are hardly ever built from scratch. Every learner comes to a topic with some amount of information, ideas and opinions about the topic. This is true even in the case where a learner cannot articulate their prior knowledge and beliefs.

In many cases, this prior knowledge is incomplete or inaccurate. Inaccurate beliefs can be termed “misconceptions” and can impede learning by making it more difficult for learners to incorporate new, correct information into their mental models. Correcting learners’ misconceptions is at least as important as presenting them with correct information. Broadly speaking, misconceptions fall into three categories:

Since The Carpentries workshops are focused on novices, and the building of strong mental models, we are most interested in the middle category of misconceptions. While teaching, we want to expose learners’ broken models so that we can help them build better ones.

Identifying and Correcting Misconceptions

How do we expose misconceptions, especially as they pertain to broken models? How can we, in-class, know whether the learners already understand this topic (so that the class can move on), and if not, what misconceptions and gaps in their knowledge we should address.

To be effective, instructors need feedback on their learners’ progress, and insight into their learners’ mental models. This feedback comes through what we call formative assessments (in contrast to summative assessment).

Summative Assessment

Summative assessment is used to judge whether a learner has reached an acceptable level of competence. Learners either “pass” or “fail” a summative assessment. One example is a driving exam, which tells the rest of society whether someone can safely be allowed on the road. Most assessment done in university courses is summative, and is used to assign course grades.

Formative assessment takes place during teaching and learning. It sounds like a fancy term, but it can be used to describe any interaction or activity that provides feedback to both instructors and learners about learners’ level of understanding of the material. For learners, this feedback can help focus their study efforts. For instructors, it allows them to refocus their instruction to respond to challenges that learners are facing.

Learners do not “pass” or “fail” formative assessments; they are simply a feedback mechanism. For example, a music teacher might ask a learner to play a scale very slowly in order to see whether they are breathing correctly, and if not, what they should change.

Formative assessment is most useful when it happens frequently (we will talk about how frequently later) and when the results are easily interpretable by the learner and instructor.

Repetition vs. Reflective Practice

The idea that ten thousand hours of practice will make someone an expert in some field is widely known, but reality is much more complex. Practice is not doing the same thing over and over again: practice is doing similar but subtly different things, getting feedback, and then changing behavior in response to that feedback to get cumulatively better. Doing the same thing over and over again is much more likely to solidify bad habits than perfect performance. This is why we emphasize practice and feedback for learners at our workshops and for trainees in our Instructor Training program.

Formative Assessments Come in Many Forms

There are many types of formative assessment, and each have their advantages and disadvantages.

Formative Assessments

Based on your previous educational experience (or even this training so far!) what types of formative assessments do you know about?

Write your answers in the Etherpad; or go around and have each person in the group name one.

One example of formative assessment that we would like to highlight is the multiple choice question (MCQ). When designed well, these can do much more than just measure how much someone knows. For example, suppose we are teaching children multi-digit addition. A well-designed MCQ would be:

Q: what is 27 + 15 ?
a) 42
b) 32
c) 312
d) 33

The correct answer is 42, but each of the other answers provides valuable insight.

Identify the Misconceptions

Choose one wrong answer and write in the Etherpad what the misconception is associated with that wrong answer. This discussion should take about 10 minutes.


  • If the child answers 32, they are throwing away the carry completely.
  • If they answer 312, they know that they cannot just discard the carried ‘1’, but do not understand that it is actually a ten and needs to be added into the next column. In other words, they are treating each column of numbers as unconnected to its neighbors.
  • If they answer 33 then they know they have to carry the 1, but are carrying it back into the same column it came from.

Each of these incorrect answers is a plausible distractor with diagnostic power. “Plausible” means that it looks like it could be right: instructors will often put supposedly-silly answers like “a fish!” on MCQs, but (a) they do not provide any insight and (b) learners actually do not find them funny. “Diagnostic power” means that each of the distractors helps the instructor figure out what concepts learners are having difficulty with.

Formative assessments are most powerful when an instructor modifies their instruction depending on the results of the assessment. An instructor may learn they need to change their pace or review a particular concept. Knowing how to respond to the results of a formative assessment is a skill that you will develop over time.

Handling Outcomes

Formative assessments allow us as instructors to adapt our instruction to our audience. What should we do as instructors if the class chooses:

  1. mostly one of the wrong answers?
  2. mostly the right answer?
  3. an even spread among options?

For one of the above, enter your answer in the Etherpad.

This discussion should take about 5 minutes.


  1. If the majority of the class votes for a single wrong answer, you should go back and work on correcting that particular misconception.
  2. If most of the class votes for the right answer, it is probably safe to move on.
  3. If answers are pretty evenly split between options, learners are probably guessing randomly and it is a good idea to go back to a point where everyone was on the same page.

Modeling Novice Mental Models

Take 10 minutes to create a multiple choice question related to a topic you intend to teach. Type it into the Etherpad and explain the diagnostic power of each its distractors, i.e., what misconception is each distractor meant to identify?

A Note on MCQ Design

  • A good MCQ tests for conceptual misunderstanding rather than simple factual knowledge. If you are having a hard time coming up with diagnostic distractors, then either you need to think more about your learners’ mental models, or your question simply is not a good starting point for an MCQ.
  • When you are trying to come up with distractors, think about questions that learners asked or problems they had the last time you taught this subject. If you have not taught it before, think about your own misconceptions or ask colleagues about their experiences.

Designing an MCQ with plausible distractors is useful even if it is never used in class because it forces the instructor to think about the learners’ mental models and how they might be broken—in short, to put themselves into the learners’ heads and see the topic from their point of view.

There are many types of formative assessments other than MCQs. One (non-exhaustive) list to supplement the earlier exercise can be found in the Edutopia assessment group.

Formative Assessments Should Be Frequent

Instructors should use a formative assessment ideally every 5 minutes and at least every 10-15 minutes in order to make sure that the class is actually learning. Since the average attention span is usually only this long, formative assessments also help break up instructional time and re-focus attention. Formative assessments can also be used preemptively: if you start a class with a question and everyone can answer it correctly, then you can safely skip the part of the lecture in which you were going to explain something that your learners already know.

How Many?

The Carpentries use formative assessments often. How many have we done since the start of this workshop? Put your guess in the Etherpad along with one example and the purpose that assessment served.

This discussion should take about 5 minutes.


This will depend on the event they are attending. Most attendees will guess low. The purpose of this exercise is to emphasize the importance of frequent formative assessments and that an individual assessment does not have to take a lot of time.

A Corollary Regarding Novices

Learners are commonly far too satisfied to not understand key points and remain confused. If learners remain confused, they are far less likely to adopt our “good enough” practices at the conclusion of the workshop. Encourage helpers to support confused learners as far as possible within the flow of the workshop.

Optional exercises

Confronting the Contradiction

Describe a misconception you have encountered in your own learning or teaching and how to get learners to confront it.

Key Points

  • Our goal when teaching novices is to help them construct useful mental models.

  • This requires practice and feedback.

  • Formative assessments provide practice for learners and feedback to learners and instructors.