Assessment of laboratory/practical work

Description

The use of a laboratory situation to assess aspects of a student’s work that may not appropriately be assessed by regular paper-based tests. A wide variety of testing objectives are possible and Brown, Bull and Pendlebury (1997) offer a long list of potential objectives which may need to be included in assessment. As a result of deciding what exactly it is that needs to be assessed, the teacher must decide whether any simple paper-and-pencil test method is adequate, or whether the laboratory needs to be the venue for assessment. Typically, students are required to perform some experimental procedure, note the results and evaluate their findings

Variations

Many, including ‘dry practicals’, where the results of a laboratory experiment are presented and students are required simply to analyse them and to evaluate and comment on them. Group work is increasingly a feature of many undergraduate programmes, reflecting the importance of collaboration skills as a course aim. But the assessment of group work brings a variety of problems (Wood, 1991).

Marking systems

These vary, depending upon the approach. Main problems surround how to balance assessment of process versus outcome/analysis/evaluation and standardizing this. The classic science paradigm (methods, results, conclusion) may assist in producing assessment criteria. Work in the assessment of medical students using objective, standardized approaches may also be helpful (Harden and Gleeson, 1979).

Advantages

This method allows assessment of a uniquely important aspect of many subjects,the ‘real world’ of scientific enquiry.

Drawbacks

There are practical difficulties towards making assessment equitable for all students: what happens if a student’s experiment ‘goes wrong’. The cost of this method of testing may be high. It is also difficult to determine assessment priorities (eg, process versus outcome) and rewards.

Orals

Oral or viva voce examinations, though commonly used in professional and postgraduate assessment, are the subject of great concern to test developers and psychometricians – especially when loosely described criteria such as ‘sparkle’ are mentioned. Orals have their attractions, but are subject to all the well-known biases and problems of selection interviews, and should only be used in the full knowledge of these problems and how these effects may be minimized. The new practitioner in higher education is counselled to beware of and avoid orals, certainly until he or she has read some of the literature (eg, Wakeford, Southgate and Wass, 1995).

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