I had an interesting conversation with a couple of colleagues yesterday, concerning the value of rubrics. I write them routinely (must be my background as an examiner at the national level), but my friends really didn’t seem to see the point. ‘You just get a feel for what’s a good essay & a bad one,’ they said, ‘and anyway we don’t have time to write a whole bunch of model answers; it’s quicker just to get in there & start marking. Besides, you can never include every possible answer. ‘ ‘And,’ they said – we were talking about rubrics for someone else to use in marking – ‘it’s far more consistent just to do it all yourself.’
I do agree that some essays spring out as being absolutely wonderful (the very first exam script I marked yesterday was a case in point: a beautifully-constructed answer to a ‘design-a-plant’ question) while occasionally you’ll also come across one that makes you feel like banging your head on the desk. But how can you be sure that you’re treating them consistently? After all, with a big class you’ll likely be marking exam scripts for several days, & your concentration & energy levels are going to vary over that time! Constructing a marking rubric before beginning the marking task will help with that.
It doesn’t have to take a heap of time either, because a rubric is most definitely not a detailed model answer. (I’ve copy-pasted one of my own from last year’s ‘cellular & molecular biology’ final exam – itself adapted from an earlier Schol Bio exam – at the bottom of this post **.) The ones I use identify the key concepts/ideas that I’m looking for, plus usually a non-exclusive list of possible examples, & the mark weighting. I’ll often change them when I’m actually doing the marking, if students are writing good answers that include options I hadn’t considered (yes, it happens!). If my team’s marking term essays, then such changes are made in consultation – something that helps ensure consistency across markers. Moderation helps there, too – check-marking a couple of papers from each of the top, middle, & bottom cohorts will quickly show if another team member’s marking is consistent with mine.
And that ability to ensure consistency is important – not only so that students can be sure that their work has been marked fairly and well, but also so that if an individual’s marking is ever questioned (let’s say, for example, that a student’s not happy with their final grade & opts for a re-mark of their year’s work), then the rubrics can be made available to a new marker to use.
I should add that, when I set the term essay questions (which I really must do Very Soon Indeed), I write the rubrics at the same time & both are available to students from the beginning of the semester.You might ask, why? And I’d say, why not? Having a good rubric to hand helps the students in so many ways, in terms of learning how to structure an essay & an argument, & also in learning some of those key critical thinking skills: they need to assess the information they’re gathering & decide what’s relevant & what’s not, & how to pull it all together. The last thing I want to be reading is a series of brain dumps, where a student’s simply written everything they know in a rather incoherent manner. Nor do I have time to help each individual student who does that sort of thing – & we used to see quite a few, before I started using rubrics in this way. Providing a marking scheme in advance saves both parties time & helps the students acquire some desirable skills. (The old adage about leading horses to water still applies, alas!)
I hasten to add that the essay rubrics don’t include information on content in the way that an exam marking rubric does! I’ve added an essay example below as well ***, so you can compare the two :-)
**Final exam question & rubric
Mammoths are closely related genetically to African elephants and similar to them in body mass. Although mammoths became extinct around 20,000 years ago, a number of individuals have been found frozen in the Arctic permafrost. Some scientists believe that it is technically possible to clone mammoths from cells in these frozen bodies, thus ‘bringing mammoths back to life’ and producing a self-sustaining wild population.
Describe how this cloning could be done – including identifying a likely species to provide surrogate mothers – and discuss the genetic and evolutionary issues associated with such work. You could consider the impact of genetic drift, inbreeding and inbreeding depression on such a population of mammoths, and their long-term prospects for survival.
Describe how cloning could be done:
- Basic description of method (3 mks)
- Identifies African elephant as likely surrogate (1 mk)
- Explains reason for this choice (2 mks)
6 Genetic drift
- Gives definition (2)
- Describes impact on population gene pool (2)
4 Inbreeding
- Gives definition (2)
- Describes impact on population gene pool (2)
4 Inbreeding depression
- Gives definition
2 For all three of the above,
- Discusses impact on population’s prospects for long-term survival from a genetic perspective. Could include eg effects of decline in heterozygosity, decreased ability to respond to evolution of pathogens/parasites, decreased fecundity
4
***Term essay question & rubric
On the basis of fossil remains, Neanderthals are viewed as a sister species to Homo sapiens. Now new data from molecular biology are changing our understanding of human evolution.
Discuss the validity of the biological species concept in the light of recent molecular data from sapiens, neandertalensis, and the Denisova hominins.
Introduction – should include a definition of the biological species concept, and the nature of ‘sister species’. /4
Briefly explain why Neandertals and modern humans have previously been viewed as sister species. How does this relate to the ‘out-of-Africa’ hypothesis for modern human origins?
/3
/2
/5
Outline the results of comparing neandertalensis and sapiens genomes, and the implications of these results.
What is the significance of the Denisova remains? (This should refer to the DNA analyses and their results.)
/3
/2
/5
How well does the biological species concept apply to Neandertals and modern humans, in the light of these findings? What are the implications for the ‘out-of-Africa’ hypothesis?
/6
Mark for content of essay
/20
