Tuesday, August 5, 2008

UbD Chapter 8: Criteria and Validity

In this second half of their discussion of Stage 2 (Assessments), the authors turn their attention to vetting the assessments we brainstormed about in Chapter 7. An assessment activity may be interesting and creative, but that's not enough; it also has to measure whether the key understandings, knowledge and skills have been attained, and it must do so in a manner that will reliably gauge the student's capabilities.

Here the authors delve into the topic of rubrics -- which, in educator-speak, specifically refers to scoring guides that list the criteria that a student's assignment must aim to reach. These are new territory for me, though I understand the logic behind them; happily, coach Page Tompkins has directed me to RubiStar, a free online service to help teachers develop quality rubrics. I'm sure I'll be making use of it as my design work progresses.

Page and I had a great conversation this afternoon, and together we separated out my various formative assessment projects from the summative assessment at the end of the unit. I hadn't distinguished between them when I was brainstorming, but as we talked it over I realized that two of my ideas were best suited to use as a summative assessment to round out the unit. One of these was the "invasive species report" that I mentioned in my previous blog post -- a truly complex task that would require a lot of prep work to make sure that the students understood what was needed. The other idea was to have the students design a brochure aimed at Amazon Basin farmers, explaining to them why trading slash-and-burn agriculture for shade-grown crops is in their own best interest.

While I like the idea of the invasive species report, it's probably better-suited to an entire class on ecology. It would require teaching the students how to perform research, weigh the validity of sources, and write a detailed paper with references. All of those are valuable scientific skills, but the project would assess those skills at least as much as the actual content of the unit. I'm more concerned at this point with establishing that the students have grasped the basics of how ecological communities work; a Scientific Skills course is better aimed at students who actually want to go into the sciences, not a survey course like freshman biology.

(Come to think of it, Scientific Skills might be a great summer elective course. I'll have to talk to Romeo and Laura about that...)

In contrast, the Amazon brochure requires fewer technical skills but more understanding of the Big Ideas of ecology: the interconnectedness of species (removing the trees destroys the "keystone" that hold the local community together), the cycling and flow of resources (the poor soils of the Amazon can't hold nutrients on their own, so without the trees the land soon becomes unproductive), and the effects of disturbance on ecological balance (the species removal and habitat destruction cause permanent shifts in the local ecology from high to low biodiversity). Presenting the argument to the farmers will also require the students to engage multiple Facets of Understanding, including Explanation, Application, Perspective, and Empathy (since they need to see the problem from the farmers' point of view -- they're just trying to feed their families, and many of the products they produce are driven to artificially-low prices by market forces that favor short-term exploitation over long-term resource management).

The brochure project can be combined with other, more traditional forms of assessment to test the students' knowledge and understanding of other aspects of the material. A test with a mixture of multiple-choice, short-answer and short-essay questions should help to cover the gaps, along with the formative assessment projects that I'll be using throughout the unit.

Now that I've chosen my end-of-unit assessment project, I'll need to come up with a rubric that is suitable for it. The two metrics suggested by the UbD authors -- Understanding and Performance -- seem like a good place to start. Proficient "Understanding", in this case, would mean that the students demonstrate a grasp of the ecological issues at play in the Amazon Basin and the negative effects of slash-and-burn agriculture; proficient "Performance" means presenting a clear and persuasive argument that acknowledges the farmers' situation while offering a better alternative. This project will also give the students a chance to engage their creative sides, if they so choose, which will probably help keep the artsy types engaged.

Time to start digging into this and get a good rubric in place.

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