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Using Blackboard to help students learn concepts in molecular biology and to assess their learning Ethan Hack, School of Biology Exercises in Stage 2 module Molecular Biology and Genomics Aim is to help students understand the structure of genes. Two computer practicals, each with two parts: 1. Interpretation of information about genes from on-line databases. 2. Interpretation of data from (made-up) experiments on regulation of gene expression (protein production). Issues • Assessment needs to check students’ understanding of concepts. • “Traditional” method – students write short answers to structured questions. • About 200 students. • Demonstrators do marking but checking is necessary – time-consuming, challenging to meet feedback deadlines. A solution? • Use Blackboard for assessment. • Blackboard provides multiple-choice, multiple-answer, and matching question types. – Multiple-choice: as expected. – Multiple-answer: more than one answer may be correct. – Matching: pair items in one column with items in other column. • Can these substitute for short answers? Converting to Blackboard 1. Interpretation of information about genes from on-line databases – reasonably straightforward. 2. Interpretation of data from (made-up) experiments on regulation of gene expression – complex. Structure of the exercises 1. Construct a scenario. 2. Give students the opportunity to make predictions. 3. To test predictions, ask ‘factual’ questions about data. 4. Interpret the results in relation to the predictions. 1. The scenario • Cells produce an enzyme called magpolase. • Regulation of magpolase production might take place in several ways. 2. Making predictions: a ‘matching’ question If magpol regulates transcription: If magpol regulates translation: If magpol regulates stability of mRNA: a. The enzyme activity should change when cells are exposed to magpol but the mRNA level should not change. b. The mRNA level should change when cells are exposed to magpol but the enzyme activity should not change. c. The change in enzyme activity when cells are exposed to magpol should correspond to the change in mRNA level. 3. ‘Factual’ questions about data 4. Interpret the results in relation to the predictions Taking into account your answers to [previous questions], what stage of gene expression do you think that magpol regulates? a. Magpol probably regulates transcription. b. Magpol probably regulates translation. c. Magpol probably regulates mRNA stability. d. There is insufficient evidence to tell what process magpol regulates. Administration Students • see all questions at once; • can change answers; • can interrupt and resume answering the questions; • have approximately one week to complete the work. Assessment outcomes • Wide spread of marks. Distribution of combined marks Curve is fitted normal distribution 25 Mean StDev N Frequency 20 15 10 5 0 0 10 20 30 40 50 60 70 80 90 100 Mark 56.75 13.84 152 Assessment outcomes • Weak (but statistically highly significant) correlation with exam results. Problems • Disappointing number of low marks. • Students can still get the wrong answer for the right reasons or the right answer for the wrong reasons. • Students can go astray and lose a lot of marks. • No way to check how students got the answer (e.g. asking a friend). • Reading complicated questions on a PC may cause difficulty and lead to ‘mechanical’ answering. Improvements to assessment 1. Include some short written answers to check reasoning. Example: Do your conclusions on the position of magpol response elements (question 15) alter your conclusion on whether magpol regulates transcription, translation, or mRNA stability (question 5)? Explain your reasoning concisely. 2. Manually adjust marks to allow for students who go astray. The Blackboard interface makes it fairly efficient to mark written answers and adjust marks. Improvements to presentation 1. Provide printed copies of the assessment. Encourage students to complete these first. 2. Examine wording carefully. Conclusions • It is possible to use Blackboard for relatively complex assessments. • It is possible to get a wide distribution of marks with ‘open’ assessments. • But it is probably best to accept human involvement in the marking. • Careful attention to presentation and wording and refinement of questions are important. • There is a tension between formative and summative aims of assessment.