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Teaching, Learning, and Grading in Science Labs

In this page — which is part of a wider range of ideas` about education in labs — we'll look at relationships between teaching, learning, and grading.  Here is a condensed summary of the full-length version:

Here is a closer examination of ideas that are summarized above.

Goal-Directed Designing of Lab Instruction

This page is a condensation of the main ideas from Teaching Scientific Methods of Thinking in Science Labs which begins with a worthy goal:  "A science lab, where students can do science and think about science, is an ideal place to teach scientific thinking skills.  By a creative use of goal-directed thinking activities in classroom labs, teachers can help students learn some of the thinking skills used by scientists in research labs."   How?

We can use a goal-directed design of curriculum` for all education, including labs, by defining goals for desired ideas-and-skills, and designing instruction with learning activities and teaching strategies that will provide opportunities for experience with these ideas & skills, and will help students learn more from their experiences.  When we design instruction, our "learning activities and teaching strategies" should include goal-directed evaluation activities that are guided by teaching strategies for why, how, and when to evaluate.

The Context of Labs:   • Usually labs are part of a wider-scope course, and are designed to support the course.   • This can be supplemented by reversed inspirations to make other aspects of a course support the goals for learning in labs.   When both of these occur (• •) there will be mutual support between the lab and non-lab parts of a course, with each helping to make the other more effective.

The rest of this page is a revision-and-condensation of ideas from "Teaching Scientific Methods of Thinking in Science Labs" about relationships between teaching, learning, and evaluating.

Formative Feedback – in Discussions and Graded Reports

In labs, a common Learning Activity` — an experience that promotes thinking and learning — is a student response (such as asking or answering questions, showing data, doing calculations, or solving mini-problems) that is written in a lab report, or discussed with the teacher, or some of each.  What are the benefits of asking students to write, or to talk-and-listen?  Based on my experience in teaching labs at two UWs, a little in Seattle and a lot in Madison:

Compared with lab reports, I think discussions are usually more educationally effective and more fun.  Most students agree.  Why?  Conscientious teachers want to provide high-quality formative feedback to help students learn, which is easier and more effective with verbal feedback (detailed, customizable in two-way conversation, and immediate, when students are thinking about their ideas & actions), compared with written feedback (delayed for too long, with much less detail) that also requires extra time for the teacher/grader.

Here is a major teaching-and-learning activity that is used in discussions (for a brief time or a longer time) during labs:

By using a reflection request, a teacher can direct students' attention to “what can be learned from an experience,” thus encouraging them to think about what they are doing, what they can learn, and why they should want to take advantage of this valuable opportunity.  A reflection request can help students improve the quality of their concentration by moving them from a minimally-aware mode (of just “going through the motions”) to a more-aware mode that is more effective for learning.  In this way a teacher can help students convert their potential opportunities for learning into actual experiences of learning, to help students learn more from their experiences.   {quoted from "Teaching Scientific Methods..."}

The Timing of Reflections:  Typically, a reflection request is much more useful when it occurs during a lab because that is when students are thinking-and-doing.  A request for reflection usually is much less effective later (when a graded lab report is returned after the lab is over) although this also can be useful, especially if it's combined with a post-lab explanation or discussion.

But... even though lab discussions are very useful (for promoting reflection and in other ways) and I prefer instructional design that encourages discussions and makes them more effective, some responses are better in writing.  And written lab reports help decrease the problems of motivation and pacing that tend to occur in labs with only discussions.  Therefore, I recommend hybrid labs that combine discussions and reports, plus exam questions.

Below are some thoughts about teaching-and-evaluating in labs by using only discussions and only written reports.  I will describe some of the strengths & weaknesses of each approach, the advantages & disadvantages.  I will not adopt a “debater's mentality” by trying to show that one approach is clearly superior by building the strongest possible argument for it, by emphasizing its advantages and ignoring its disadvantages.  After five sections — about Learning & Fun, Extrinsic Motivation for Students, Teacher vs Judge, Problems with Pacing, and Quality of Teachers — we'll explore some of the many options for combining different methods of teaching-and-evaluating in Hybrid Labs`.

Should we evaluate student performance during discussions?  I encourage teachers to carefully consider the pros & cons (the reasons to say yes, no, or maybe not) and decide.  After doing this, I almost always avoid evaluation during discussions, and the sections below assume that discussions are not being evaluated.

More Learning and More Fun

In lab, usually discussions between students & teacher will help students learn more and have more fun.  Why?  Learning is better because formative feedback is usually much better with discussions than in written reports.  And interactive discussions are more fun, for a variety of reasons that are both intellectual and social.

Student Motivation from Lab Grades

The extrinsic motivation of working for a grade, which is an important part of the total motivation for most students, is missing in a discussion-only lab where — if discussions are graded pass/fail (so students get full points for participation) and if all students have participated in each planned discussion-activity during a lab — all student get the same grade.  Although students also will study for other reasons — because total motivation includes rewards that are extrinsic plus intrinsic, personal, and interpersonal — the desire to get a high lab grade will motivate most students.

David Perkins (1 2) proposes that "people learn much of what they have a reasonable opportunity and motivation to learn," and lab grades provide extrinsic motivation.  This motivational factor is a reason to supplement discussions with accountability — in lab reports and/or post-lab exam questions about ideas-and-skills from lab — to give students more responsibility and “ownership” of their work, in a hybrid lab.

Also, if "all student get the same grade" this can be a practical problem in courses where the instructor has decided – usually for motivational reasons – to give lab grades a medium-to-heavy weighting in the “total points” used for assigning course grades.    { some of my thoughts about Weighting of Lab Grades }

Teacher versus Judge — Is there a tension?

In well-designed lab education, the roles of teacher and judge should be mutually supportive, as when lab grades provide extrinsic motivation leading to effort and learning.

But when combining lab discussions with lab reports, tensions occur.  When I'm teaching labs, one benefit of discussions is the immediate detailed feedback I can give students.  This is easier in discussion-only labs when there is no grading, because I can focus my full attention on teaching (rather than judging) and students can focus on learning (rather than being judged).  Because I am only a teacher (and not also a judge) I can ask and answer any question freely, thinking only about what is best for helping students learn.  When I decide to withhold information — for example, by asking a question instead of giving a direct answer — my only motivation is pedagogical, and the purpose is to challenge students with an inquiry mini-activity (and adjust its difficulty) for the purpose of making them think, to let them play a more active role in their own learning.  I never have to worry about whether I am being unfair by giving too much information to one group (but not others) about a question that later will be used to assign a grade on their lab report.*  This is a liberating experience for me, and is educationally beneficial for my students.  And if discussions are not graded, students feel similarly free because they can ask any questions they want without fear that they will get a lower grade because their questions show a lack of understanding.

* For example, if I see Joe and Sue (working as lab partners) writing a lab-report response in a wrong way, should I provide coaching – with questions, hints, and explanations – that will help them understand what they were doing wrong and how to do it better?  Or should I remain silent and let them continue doing it wrong, so I can take points off on their report?  As a judge, silence is appealing because it's more fair to students who did not get a personal warning that would have prevented them from getting it wrong, or who figured it out on their own without help.  But for Sue and Joe the result of silence is that they won't get feedback until later (when they see points lost on their lab report, with minimal written “explanations for why” from me) and by this time their teachable moment is far in the past, and they probably won't think much about the experience or learn from it.  My instincts as a teacher are to teach NOW, during the lab while they're thinking, deciding, and doing, but if I'm also a judge this is more difficult and my effectiveness as a teacher is diminished.

This section has described an indirect tension between discussing and grading a written lab report.  There also can be direct tensions -------- [[ I.O.U. – Later, I'll finish this paragraph. ]]

Problems with Pacing

A lab with scheduled discussions has an imbalance of supply-and-demand due to unequal numbers, because there is one teacher and many students.  Although this problem cannot be eliminated, it can be reduced by using these strategies:

• fewer groups for discussions:  The numerical imbalance can be reduced by asking students to organize themselves into larger groups.  For example,... {details}

• better skills:  Teachers can improve their skill in leading discussions, to use time more efficiently so all discussions will fit into a lab session.

• productive waiting:  When students must wait for the teacher to finish discussions with other students, they can... {details}

• improved timings:  We can design each lab so discussions are evenly spaced throughout it (not delayed until near the end) and productive activities are always available.

• fewer topics for discussion:  We can design hybrid labs that combine discussions (for some questions) with a written report (for other questions).  This reduces the number of discussions, and adds another productive activity – writing the report – that students can do while waiting.  The quality of the remaining planned discussions may increase because the pacing can be more leisurely.  Teachers also will have more time to interact with students informally in unplanned discussions that occur while walking around the lab-room to check on labwork progress and respond to student-initiated questions.

Quality of Teachers

In a lab where discussions are emphasized, the learning experience of students depends on interactions with their teacher, so...

What happens if students get a teacher with less ability, experience, or motivation?  This question is especially important for a large college course with many labs, taught by many graduate students who have a wide range of experience & abilities.

Quality of Teachers:  Teaching Scientific Method in Science Labs looks at my own experiences` with “working the room” during lab;  four types of teachers;  preparing teachers to be skilled discussion leaders;  and uniformity among teachers.

Uniformity among Teachers:  Whether in leading discussions or grading reports, we cannot achieve total uniformity so (as explained in My Philosophy of Lab Education) I think:  we should try to achieve quality with a “greatest good for the greatest number of students,” not an impossible uniformity in teaching & grading;*  instead of a mandatory rubric-system for grading, we should give TAs non-compulsory guidelines and recommendations;**  and regarding Justice in Grading, "almost always the best way to get approximate uniformity and justice is to normalize lab grades... [after explaining to TAs & students] what normalizing is, why (because it's the most fair way to grade) it will be used, and [because options-for-normalizing exist] how it will be done."

* Even if all graders use the same rubric-system, this will not produce uniform grading because each grader must decide how to assign a number for each report in every category.  These decisions will produce differing results, with some graders assigning higher points, and some lower.  Or, if each TA is responsible for achieving a specific average, the normalizing is not avoided, it's just shifted to individual TAs, with an extra constraint that is a time-wasting burden for them.  But when normalizing is used the focus of grading becomes quality instead of uniformity.  Each TA is free to grade the way they want, with their focus on quality, deciding how to assign relative grades “on a curve” within their own sections, because normalizing will compensate for differences between TAs.

** Experienced graders can describe the grading strategies they have developed that let them enjoy lab-grading the most (or dislike it the least) because these strategies let them grade well in a reasonable time with a feeling of justice, to produce a higher ratio of “personal satisfaction / time invested”.

A Wider Range of Ideas about Lab Education

My Philosophy of Lab Education covers a variety of topics:  Uniformity among Teachers` (is it possible? desirable? what should be our goals, and why?  can we achieve Justice in Grading with a compulsory rubric? by normalizing?) as described above, plus Educational Collaborations (with instructors, TAs, other lab directors,...) and My Personal History with Lab Education and more.

In a multi-TA course, if "all student get the same grade" this is a problem if the instructor has decided (usually for motivational reasons) to give lab grades a significant weighting when assigning course grades.    { my views on Weighting of Lab Grades }

Hybrid Labs — Combining Benefits

This section reviews the benefits & drawbacks of discussion-only labs (with no written reports) and reports-only labs (with no scheduled discussions).  Then it explains the advantages of hybrid labs that combine discussions with reports in a “best of both” designing of instruction.

Labs with only Oral Discussions

The previous set of sections` describes pros & cons of labs with only discussions.  Here is a summary.

pros:  Students often have More Fun & More Learning due to better formative feedback;  and tensions of Teacher versus Judge are reduced.

cons:  Without the personal accountability of graded reports, valuable extrinsic motivation is decreased;*  and too many discussions during a lab period can cause problems with pacing.

* Although it can be done, should we grade discussions?

Another factor to consider is the quality of teachers and related questions about uniformity & justice.

Labs with only Written Reports

pro:  When students report their thoughts in writing (by "answering questions, showing data, doing calculations, solving mini-problems,...") this can be a valuable thinking activity that leads to learning, if the assigned responses (what we ask them to write) are well designed.

con:  With graded reports, students get a lower quality of formative feedback — because it has less detail and is delayed — compared with discussions in lab.  Of course, asking students to write reports does not mean “no discussions are allowed” is the lab policy, and improvised conversations still occur, especially those begun by students, and anything related to lab safety.  But when discussions are not scheduled during a lab, they are less likely to occur, and are less likely to have significant ideas-and-skills content.

con:  The grading itself also limits freedom of discussion because when an idea will be graded in a report, a teacher who wants to be fair will not discuss this idea with some students but not others.  This effort to be fair can reduce teaching effectiveness, in a conflict of teaching versus judging.

We can think about pros & cons for students (above) and also for teachers.

con:  In a feeling that I think is shared by most teachers, I usually don't enjoy grading lab reports because it requires a lot of time, and produces only a small amount of satisfaction, so it has an extremely low ratio of satisfaction/time.   For me, the level of satisfaction is usually low for two reasons:  mainly it's because my efforts are not very effective in helping students learn ideas & skills, due to the minimal-and-delayed formative feedback;  also, grading reports requires a lot of time to make a small difference in a student's course grade, compared with quick-and-easy grading decisions about points on quizzes and exams;  and usually a quiz or exam has a much higher “spread between students” (e.g. as measured by standard deviation) than with a lab report.   But the grading experience can improve if we...

Design for Grading:  When teachers grade lab reports, their ratio of “personal satisfaction / time invested” can be increased by designing reports for grading that is quicker-and-easier.  How?  We can make grading more efficient by carefully choosing the content & format of student responses (what we ask them to write & how), and make reports shorter (perhaps combined with reducing the weighting of lab-grades when determining a course-grade) by moving some responses from reports into discussions and post-lab testing, as explained below.

Hybrid Labs — with Discussions + Reports, and More

Moving Responses between Discussions & Reports

A simple way to partially solve these problems in a pure lab (with only discussions, or only reports) is to convert a pure lab into a hybrid lab, either by moving some activities from discussions into a report (to improve extrinsic motivation, and decrease problems of pacing) or, in a reverse action, by moving some activities from a report into discussions (to improve formative feedback, and reduce tensions between teaching & judging).

converting from only-reports to hybrid:  When an idea will be graded in a report, so a teacher does not want to "discuss this idea with some students but not others," some aspects of the idea can be included in a scheduled discussion, so all students will have the same information.  This discussion — which can be part of a teaching strategy to adjust the level of difficulty — improves the formative feedback and decreases teacher-vs-judge tensions.  Or, for some questions a teacher might adopt a policy of giving feedback during lab with a thumbs up (ok as-is) or thumbs down (not ok) or sideways (partially ok), and then let students revise their answer, either with or without hints from the teacher about how to revise.  Or an idea can be totally removed from a report, so it's only discussed.

converting from only-discussions to hybrid:  Some ideas can be moved (partially or totally) from discussions into a report, to increase extrinsic motivation and improve pacing.

You also can move activities, one way or the other, to “shift the balance” in a hybrid lab that already is part-discussions and part-reports.

Educational Design includes Evaluation Activities

This page begins with a process of goal-directed design in which we define educational goals (for ideas-and-skills, plus motivations & attitudes) that will guide us in designing instruction with useful learning activities and teaching strategies.  When instruction is designed effectively there will be mutual support between goals (for what students should learn) and motivations (so students want to learn) and activities (offering opportunities to learn) which include evaluation activities that reliably-and-accurately measure appropriate knowledge by testing ideas-and-skills that are the educational goals, and (in well designed instruction) have been the focus of teaching and learning.

Options for Grading Labs

Lab Grades:  In labs, ideas-and-skills can be evaluated in many ways:  by a grading of reports, or discussions (but should we?), and pre-lab quizzes, and with post-lab testing (*) by putting lab-related questions on regular tests (in a small quiz or big exam), or in special lab-tests with responses that are written or oral.  Some labs can include built-in accountability for work that is qualitative (identifying an unknown chemical,...) or quantitative (determining the concentration of a solution,...), with students getting more points for coming closer to the correct answer.

Course Grades:  Teachers can combine some of these grading-inputs, or all, to determine a lab grade.  In a lab course, the lab grade is the course grade.  In the more frequent non-lab courses, lab grades are only one factor (among many) in determining an overall course grade, so we ask how much should lab grades be weighted?

* Using post-lab testing (of what is being learned in lab) will motivate students to view discussions & reports as opportunities to learn ideas-and-skills that later will be tested.

But ... it's difficult to write exams (for labs or in general) to test higher-level thinking skills.