Page 8 – iteration, making, building, and coding in education

Rubrics and Numerical Grades – Hacking the 100-Point Scale, Part 3

As part of thinking through my 100-point scale redesign, I’d like you to share some of your thoughts on a rubric scenario.

Rubrics are great for how they clearly classify different components of assessment for a given task. They also use language that, ideally, gives students the feedback to know what they did well, and where they fell short on that assessment. Here’s an example rubric with three performance levels and three categories for a generic assignment:

I realize some of you might be craving some details of the task and associated descriptors for each level. I’m looking for something here that I think might be independent of the task details.

The student shown above has scores of 1, 2, and 3 respectively for the three categories on this assignment, and all three categories are equally important. Suppose also that in my assessment system, I need to identify a student as being a 1, 2, 3, or 4 in the associated skills based on this assessment.

More generally, I want to be able to take a set of three scores on the rubric and generate a performance level of the student that earned them. I’d like to get your sense of classifying students into the four levels this way.

Here are the rubrics I’d like your help with:

I’ve created a Desmos Activity using Activity Builder to collect your thoughts. I chose Activity Builder because (a) Desmos is awesome, and (b) the internet is keeping me from Google Docs.

You can access that activity here.

I’ll be using the results as an input for a prototype idea I have to make this process a bit easier for all involved. Thanks in advance!

Hacking the 100-Point Scale – Part 2

My previous post focused on the main weakness of the 100-point scale which is the imprecision with which it is defined. Is it percentage of material mastered? Homework percentage completion? Total points earned? It might be all of these things, or none of them, depending on the details of one person’s grade book.

Individual departments or schools might try to define uniformity in grading policies, give common final assessments, or spread grading of final exams amongst all teachers to ensure fairness. This might make it easier to compare two students across a course, but still does not clearly define what the grade means. What, however, does it signify that a student in an AP course has an 80 while a student in a regular section of the same course has a 90?

Part of the answer here is based in curriculum. Understanding what students are learning and in what order defines what is being learned, and would add some needed information to compare the AP and regular students just mentioned. The other part is assessment: a well crafted assessment policy based in learning objectives and communicated to a student helps with understanding his or her progress during the school year. I hope it goes without saying that these two components must be present for a teacher to be able to craft and communicate a measure of the student’s learning that students, teachers, parents, and administrators can understand.

At this point, I think the elementary teachers have the right idea. I’ve been in two different school systems now that use a 1 – 4 scale for different skills, with clear descriptors that signify the meaning of each level. Together with detailed written comments, these can paint a picture of what knowledge, skills, and understanding a student has developed during a block of the school year. These levels might describe the understanding of grade level benchmarks using labels such as limited, basic, good, and thorough understanding. These might classify a student using the state of their progress with terms like novice/beginner/intermediate/advanced. The point is that these descriptors are attached to a student and ideally are assigned after reviewing the learning that the student has done over a period of time. I grant that the language can be vague, but this also demands that a teacher must put time into understanding the criteria at his or her school in order to assign grades to a particular student.

When it comes to the 100 point scale, it’s all too easy to avoid this deliberate process. I can report assignments as a series of total point values, and then report a student’s grade as a percentage of the total using grade book software. Why is a student failing? He didn’t earn enough points. How can he do better? Earn more points. How can he do that? Bonus assignments, improving test scores, or by developing better work habits. The ease of generating grades cheapens the deliberate process that may (or may not) have been involved in generating them. Some of the imprecision of the meaning of this grade comes, ironically, from an assumption that the precision of a numerical grade makes it a better indicator. It actually requires more on the part of the teacher to define components of the grade clearly using numerical indicators, and defining these in a way that avoids unintended consequences requires a lot of work to get right.

Numerical grades inform a student’s progress, but don’t tell the whole story. The A-B-C-D-F grading system hasn’t been in use in any of the schools where I’ve taught, but it escapes some of the baggage of the numerical grade in that it requires that the school report somehow what each letter grade represents. An A might be mapped from a 90-100% average in the class, or 85-100 depending on the school. As with a verbal description, there needs to be some deliberate conversation and communication about the meaning of those grades, and this process opens the door for descriptors for what grades might represent. Numerical grades on the 100 point scale lack this specificity because grades on this scale can be generated with nothing more than a calculation. That isn’t to say that a teacher can’t put in the time to make that calculation meaningful, but it does mean it’s easy to give the impression of precision that isn’t there.

Compounding the challenge of its imprecision is the reality that we use this scale for many purposes. Honor roll or merit roll are often based in having a minimum average over courses taken in a given semester. Students on probation, often measured by having a grade below a cut-off score, might not be able to participate in sports or activities. Students with a given GPA have automatic admission to some universities.

I’m not proposing breaking away from grading, and I don’t think the 100 point scale is going away. I want to hack the 100 point scale to do a better job of what it is supposed to do. While technology makes it easier to generate a grade than it used to be, I believe it also provides opportunity to do some things that weren’t feasible for a teacher to do in the past. We can improve the process of generating the grade to be a measure of learning, and in communicating that measure to all stakeholders.

Some ideas on this have been brewing as I’ve started grading finals and packing for the end of the year. Summer is a great time to reflect on what we do, isn’t it?

Hacking The 100-Point Scale – Part 1

One highlight of teaching at an international school is the intersection of many different philosophies in one place. As you might expect, the most striking of these is that of students comparing their experiences. It’s impressive how the experienced students that have moved around quickly learn the system of the school they are currently attending and adjust accordingly. What unites these particularly successful students is their awareness that they must understand the system they are in if they are to thrive there.

This is the case with teachers, as we share with each other just as much. We discuss different school systems and school structures, traditions, and assessment methods. Identifying the similarities and differences in general is an engaging exercise. In general, these conversations lead to a better understanding of why we do what we do in the classroom. Also, in general, these conversations end with specific ideas for what we might do differently on the next meeting with students.

There is one important exception. No single conversation topic has caused more argument, debate, and unresolved conflict at the end of a staff meeting than the use of the 100-point scale.

The reason it’s so prevalent is that it’s easy to use. Multiply the total points earned by 100, and then divide by the total possible points. What could go wrong with this system that has been used for so long by so many?

There a number of conversation threads that have been particularly troublesome in our international context, and I’d like to share one here.

“A 75 isn’t a bad score.”

For a course that is difficult, this might be true. Depending on the Advanced Placement course, you can earn the top score of 5 on the exam by earning anywhere between around 65% and 100% of the possible points. The International Baccalaureate exams work the same way. I took a modern physics exam during university on which I earned a 75 right on the nose. The professor said that considering the content, that was excellent, and that I would probably end up with an A in the course.

The difference between these courses and typical school report cards is that the International Baccalaureate Organization (IBO), College Board, and college professor all did some sort of scaling to map their raw percentages to what shows up on the report card. They have specific criteria for setting up the scaling that goes from a raw score to the 1 – 5 or 1 – 7 scores for AP or IB grades respectively.

What are these criteria? The IBO, to its credit, has a document that describes what each score indicates about a student with remarkable specificity. Here is their description of a student that receives score of 3 in mathematics:

Demonstrates some knowledge and understanding of the subject; a basic sense of structure that is not sustained throughout the answers; a basic use of terminology appropriate to the subject; some ability to establish links between facts or ideas; some ability to comprehend data or to solve problems.

Compare this to their description of a score of 7:

Demonstrates conceptual awareness, insight, and knowledge and understanding which are evident in the skills of critical thinking; a high level of ability to provide answers which are fully developed, structured in a logical and coherent manner and illustrated with appropriate examples; a precise use of terminology which is specific to the subject; familiarity with the literature of the subject; the ability to analyse and evaluate evidence and to synthesize knowledge and concepts; awareness of alternative points of view and subjective and ideological biases, and the ability to come to reasonable, albeit tentative, conclusions; consistent evidence of critical reflective thinking; a high level of proficiency in analysing and evaluating data or problem solving.

I believe the IBO uses statistical and norm referenced methods to determine the cut scores between certain score bands. I’m also reasonably sure the College Board has a similar process. The point, however, is that these bands are determined so that a given score matches

The college professor used his professional judgement (or a bell curve, I don’t actually know) to make his scaling. This connects the raw score to the ‘A’ on my report card that indicated I knew what I was doing in physics.

The reason this causes trouble in discussions of grades in our school, and I imagine in other schools as well, is the much more ill-defined definition of what percentage grades mean on the report card. Put quite simply, does a 90% on the report card mean the student has mastered 90% of the material? Completed 90% of the assignments? Behaved appropriately 90% of the time? If there are different weights assigned to categories of assignments in the grade book, what does an average of 90% mean?

This is obviously an important discussion for a school to have. Understanding the meaning of the individual percentage grades and what they indicate about student learning should be clear to administrators, teachers, parents, and most importantly, the students themselves. These is a tough conversation.

Who decided that 60% is the percentage of the knowledge I need to get credit? On a quiz on tool safety in the maker space, is 60% an appropriate cut score for someone to know enough? I say no. On the report card, I’d indicate that a student has a 50 as their grade until they demonstrate he or she can get 100% of the safety questions correct. Here, I’ve redefined the grade in the grade book as being different from the percentage of points earned, however. In other words, I’ve done the work of relating a performance measure to a grade indicator. These should not be assumed to be the same thing, but being explicit about this requires a conversation defining this to be the case, and communication of this definition to students and teachers sharing sections of the same course.

Most of this time, I don’t think there is time for this conversation to happen, which is the first reason I believe this issue exists. The second is the fact that a percentage calculation is mathematically simple and understood as a concept by students, teachers, and parents alike. Grades have been done this way for so long that a grade on the 100-point scale is generally assumed to be this percentage mastered or completed concept.

This is too important to be left to assumption. I’ll share more about the dangers of this assumption in a future post.

Building Functions – Thinking Ahead to Calculus

My ninth graders are working on building functions and modeling in the final unit of the year. There is plenty of good material out there for doing these tasks as a way to master the Common Core standards that describe these skills.

I had a sudden realization that a great source for these types of tasks might be my Calculus materials. Related rates, optimization, and applications of integrals in a Calculus course generally require students to write models of functions and then apply their differentiation or integration knowledge to arrive at a result. The first step in these questions usually involves writing a function, with subsequent question parts requiring Calculus methods to be applied to that function.

I dug into my resources for these topics and found that these questions might be excellent modeling tasks for the ninth grade students if I simply pull out the steps that require Calculus. Today’s lesson using these adapted questions was really smooth, and felt good from a vertical planning standpoint.

I could be late to this party. My apologies if you realized this well before I did.

Problems vs. Exercises

My high school mathematics teacher, Mr. Davis, classified all learning tasks in our classroom into two categories: problems and exercises. The distinction between the two is pretty simple. Problems set up a non-routine mathematical conflict. Once that conflict is resolved once, problems cease to be problems – they become exercises. Exercises tend to develop content skills or application of knowledge – problems serve to develop one’s habits of mathematical practice and understanding.

I tend to give a mixture of the two types to my students. The immediate question in an assessment context is whether my students have a particular skill or can apply concepts. Sometimes this can be established by doing several problems of the same or similar type. This is usually the situation when students sign up for a reassessment on a learning standard. In cases where I believe my students have overfit their understanding to a particular question type, I might throw them a problem – a new task that requires higher levels of understanding. I might also give them a task that I know is similar to a question they had wrong last time, with a twist. What I have found over time is that there needs to be a difference between what I give them on a subsequent assessment, or I won’t get a good reading on their mastery level.

The difficulty I’ve established over the past few years learning to use SBG has been curating my own set of problems and exercises for assessment. I have textbooks, both electronic and hard copy, and I’ve noted down the locations of good problems in analog and digital forms. I’ve always felt the need to guard these and not share them with students so that they don’t become exercises. My sense is that good problems are hard to find. Good exercises, on the other hand, are all over the place. This also means that if I’ve given Student A a particular problem, that I have to find an entirely different one for Student B in case the two pool their resources. In other words, Student A’s problem then becomes Student B’s exercise. I haven’t found that students end up thinking that way, but I still feel weird about using the same problem multiple times.

What I’ve always wanted was a source of problems that somehow straddled the two categories. I want to be able to give Student A a specific problem that I carefully designed for assessing a particular standard, and student B a different manifestation of that same problem. This might mean different numbers, or a slight variation that still assesses the same thing. I don’t want to have to reinvent the problem every single time – there must be a way to avoid repeating that effort. By carefully designing a problem once, and letting, say, a computer make randomized changes to different instances of that problem, I’ve created a task I can use with different students. Even if I’m in the market for exercises, it would be nice to be able to create those quickly and efficiently too. Being able to share that initial effort with other teachers who also share a need would be a bonus.

I think I’ve made an initial stab at creating something to fit that need.

Exploring Functions (and Non-Functions) Interactively

Heeding Dan’s encouragement to step things up in his NCTM talk, I revisited an introduction to functions activity that I put together three years ago. The idea is to get students to make observations about inputs and outputs and use the ‘notice and wonder’ parlance from the Math Forum to prompt conversations about these ideas.

I rewrote the activity with some deliberate changes and webified it to make it easy to access and share – you can find it here:
http://emwdx.github.io/functions-exploration/index.html

The activity has a few elements that I want to highlight with the hope that you might consider (a) trying the activity with your students or (b) downloading the code for the activity, tweaking it, and then re-sharing it with your enhancements.

Students go through the modeling cycle multiple times.

The activity begs students to take a playful approach. Change the input value and watch the output. Predict what’s going to happen and see if your mental model is correct. Then do the next one, and the next.

Arithmetic isn’t necessarily a prerequisite.

Some students were actually more puzzled by the functions that took text inputs. They experimented nevertheless to figure out what was happening, and some noticed that the pattern worked for numbers too.

Controversy is built in.

Students working on Functions 5 and 6 saw nothing weird happening when they worked alone. When they then went to share their answers with classmates, the latter function started some really interesting interactions between students trying to figure out who was wrong.

Students of different levels all succeeded and all struggled at some point.

One student zipped through the arithmetic exercises and then got stuck figuring out Function 3 or 7. Some of the weaker students jumped around and got Functions 1 and 4 and 8, which is enough to get in the game of finding patterns and drawing conclusions. A higher level student experimented with Function 7 to find that there was a well defined range for the outputs – random, but with limitations.

The need for definitions came out of the activity, not the other way around.

Students felt the need to clearly define the behavior of Functions 6 and 7 as being different than the others in a fundamental way. Definitions for relations and functions weren’t huge cognitive jumps for students since there was a recently established context. It’s also important to notice that the definition for relations that aren’t functions has to be more than just the lack of a pattern. Function 6 helps with this.

Many of the CCSS standards for mathematical practice are embedded within.

…as are some of the high school standards for functions.

If you try this with students, let me know how it goes.

Technical Details:

If you want to try this yourself, you can download the code from Github here:
https://github.com/emwdx/functions-exploration/tree/gh-pages

I did this also as an attempt to whip together something using the React JS library which I’ve been learning recently. It makes for a really nice interface for building this type of interactivity into a webpage. There will be more, so stay tuned.

The React components for the eight functions are in lines 86-102 of the index.html file. The function definitions used by each component are defined toward the bottom of the code in that file. You could change these around using Javascript to make these functions fit with your vision of this activity for students. The file is self contained, so you share just the HTML file you change with students, the page will function correctly.

Happy coding!

The Incredible Growing Bricks

I put together this three-act activity two years ago, and decided to include it in the playlist for this year’s Math 9 course. The students got right to work in figuring out the total mass of the three bricks together.

This time, I circulated the actual bricks among the students as they worked. I opted not to do this two years ago because I wanted to force them to use the dimensions in the image above to find their answers. The result was that some students chose to make the measurements themselves rather than use the image. This yielded some great interactions between students asking if the bricks were proportional to each other, and those assuming they were proportional. There were some excellent examples of strong explanations involving proportional reasoning among the student work, as well as typical examples of misconceptions, such as the mass being proportional to the scale factor between the sides.

I also did something new with this modeling task and asked students to predict their uncertainty. Often times, students see that they were close to the actual answer revealed in the third act (but not exactly equal), and subsequently classify their answers as wrong. The uncertainties allow more flexibility in this regard. It also revealed some misunderstanding of the relationship between uncertainty and reporting answers that wasn’t unexpected: one student gave 16.895 grams, with an uncertainty of plus or minus 0.1 grams. This is a frequent issue in science classes, but not something I’ve addressed with mathematics students in the past.

Trigonometric Graphs and the Box Method

Graphing trigonometric functions is a crucial skill, but there is a lot of reasoning involved in the process. I learned the method that follows from a colleague in my first years of teaching in the Bronx, and used it later on when I actually taught Algebra 2 and PreCalculus.

Here’s an example for f(x) = 2 cos(2x) + 3:

Students first (lightly) draw a box that is one period wide, twice the amplitude tall, and centered vertically on the midline of the sinusoid. The process of doing this isolates the reasoning about transformations of the function from the actual drawing of the graph, which also takes some skill. I usually ask students to state the period, amplitude, and average value anyway, but this method implicitly requires them to find these quantities anyway. We use the language of the amplitude, period, and average value to describe this box and the transformations of the parent function.

Once the box is in the right place, then we can focus on the graphing details. Is it a cosine or sine? How does the graph of each fit into the box we have drawn? Where does the curve cross the midline? This conversation is separate from the location and dimension conversations, and this is a good thing. The shape of the curve merits a separate line of reasoning, and encouraging that separation through this method reduces the cognitive demand along the way. I have also seen that keeping this shape conversation separate has reduced the quantity of the pointy sawtooth graphs that students inevitably produce.

I have considered doing this for other parent functions, but haven’t been convinced of the potential payoff yet compared with the perfect fit thus far of the trigonometric family of functions. Thoughts?

Hosting Meteor JS Applications – My Process on Webfaction

There has been some interest expressed here and on Twitter for a description of the process of moving an application from the free meteor.com to my own server. I run my web applications (such as this blog) on Webfaction, which gives a lot of flexibility for setting up a number of different hosted services. I won’t say each step below is easy and as straightforward as it sounds, so feel free to add your difficulties to the comments below, and I’ll elaborate. Having the steps in one place will hopefully be as useful for you as it likely will be for me.

Note: Steps 1 – 3 in the list below are just for downloading data you may have collected in an online application onto your computer. If you don’t care about the online data, you can skip down to step 4.

I installed Mongo on my local machine from http://www.mongo.org
In a terminal on my local machine, I entered meteor mongo --url my-app.meteor.com to get the username, password, url, port, and database name from the *.meteor.com website. The result is a URL that contains the information you will need for the next step: (username:password@url:port/databasename)
save the data onto my local computer using mongodump --host hostname:port --db databasename -u username -p password -o ~/Desktop where the information from the last step replaces the username, password, etc.
To create a packaged version of the app that runs on my computer, go to the Meteor project directory, and type meteor build --architecture os.linux.x86_64 ./ . This assumes that the server that will be running your project is a Linux machine…but this assumption is probably a good one for most hosting services.
Create a free account on mLab (http://www.mlab.com). The free account gives you 500 MB of space for databases. For comparison, the total size of my most-used application is only 2.7 MB. I think you’ll have enough space. The important thing to get, once you have a database set up, is called the URI. If you create a database, there is a box at the top of the page that gives you information that looks like this: mongodb://:@dsXXXXXXX.mlab.com:PORT/DATABASENAME which you will need in the next step.
I learned the Webfaction specific steps from reading this page, though you won’t need to do the Mongo steps if you are using mLab as I am. On the Webfaction server, you must install node. You can do this by following the steps here. You must also create a custom WebSockets application. This will give you a port number that you will need in the step below where local variables are set.
Again, this is a Webfaction specific instruction, but you need to attach the application to a domain/URL where your application will be accessed. Save this URL
Once you have created the WebSockets app, upload the .tar file (from step 4) to the /webapps/web-sockets-application directory through ftp and unpack with tar -xzf my-app.tar.gz
Using the mLab information from step 5, the port number from step 6, and the location of the node application from step 6, you’ll need to fill in the appropriate parts of the commands below:

export MONGO_URL="mongodb://:@dsXXXXXXX.mlab.com:PORT/DATABASENAME?autoReconnect=true" # 2
export MAIL_URL='email-address-for-sending-mail-from-your-app'
export PORT="PORT-NUMBER-FROM-STEP-6"
export ROOT_URL="DOMAIN-FOR-APPLICATION-FROM-STEP-7"
export PATH=~/webapps/node/bin/:$PATH
Almost there, folks. Inside the unpacked .tar directory (which will be called /bundle), enter the /bundle/programs/server/packages directory and run npm install
Go back to the /bundle directory and run nohup node main.js . This terminal command will run a command continuously on the shell, even if you close the terminal.
If you’ve made it this far, you might just have your Meteor app running on your own server.

I hope this helps you, but if you run into trouble, throw a comment below and I’ll see if I can help.

Taking Time Learning Math: A Student’s Perspective

Yesterday was our school’s student led conference day. I’ve written previously on how proud these days make me as an educator. Whens students do genuine reflection on their learning and share the ups and downs of their school days, it’s hard not to see the value of this as an exercise.

During one conference, a student shared a fascinating perspective on her learning in math. This is not the usual level of specificity that we get from our students, so I am eager to share her thinking. Here’s the student’s comment during the conference:

“It isn’t that I don’t like math. Learning takes time in math, and I don’t always get the time it takes to really understand it.”

I asked her for further clarification, and this was her response:

…Math is such an interesting subject that can be “explored” in so many different ways, however, in school here I don’t really get to learn it to a point where I say yeah this is what I know, I fully understand it. We move on from topic to topic so quickly that the process of me creating links is interrupted and I practice only for the test in order to get high grades.

It’s certainly striking to get this sort of feedback from a student who is doing all the things we ask her to do. The activities this student is doing in class are not day-after-day repetitions of “I do, we do, you do” – we do a range of class activities that involve exploring, questioning, and interacting with other students.

This student’s comment is about limitations of time. She isn’t saying that we aren’t doing enough of X, Y, or Z – quite the contrary, she just is asking for time to let it sink in. She doesn’t answer the question of what that time looks like, but that’s not her job, it’s ours.

I know I always feel compelled to nudge a class forward in some way. This doesn’t mean I moving through material more quickly, but I do push for increased depth, intuition, or quality conversation about the content in every class period. Her comment makes me realize that something still stands to be improved. Great food for thought for the weekend.

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