About Computer-Based Assessment

What is Computer-Based Assessment (CBA)?

Computer-Based Assessment (CBA) is assessment which is both delivered and marked by computer (JISC, 2007:6). This distinguishes it from Computer Assisted Assessment (CAA), in which the computer is only used in part of the process of assessment (see Computer-Assisted Assessment).

CBA can be used for summative, formative or diagnostic assessment purposes, with or without associated feedback being automatically delivered to students. Computer-based assessments are typically based on multiple choice questions (MCQs) or other 'objective' question types, although non-objective questions (e.g. essay, short answer) can also be included. Development of a successful assessment requires careful consideration of design and delivery issues, which differ from paper-based assessment.

Why use CBA?

CBA can be used to help increase the frequency of assessment (without necessarily increasing the marking load), to offer immediate feedback and to make tests accessible anytime and anywhere. It is also possible to create a number of assessments which draw from a single, shared question bank (in NOW this is called a Question Library). This allows for the re-use of questions, and for their order to be randomised within a given assessment. Feedback on student performance can be automatically delivered on a question-by-question basis, or for the whole assessment.

CBA has also been used to simulate practice-based activities which traditional paper and pen assessments fall short of replicating, for example by incorporating video and audio. Many instances of this use can be found in clinical subjects, for example.

Bull and McKenna (2004) cite the following reasons to use CBA:

The table below shows some of the more common rationales for using CBA, alongside their associated benefits.

Table: Rationales for using CBA, and associated benefits

I want to...Benefit of CBA
Provide additional diagnostic or formative assessment opportunities. Detailed feedback can be built into CBA assessments, whether the main focus is diagnostic, formative or summative.
Provide timely feedback. Feedback can be delivered immediately and/or automatically. This can be particularly useful for formative use.
Mark work quickly. Tests are marked automatically and consistently by the computer
Increase the flexibility of assessment delivery. CBA tests can be made available anytime, anywhere. The duration of the test, period for which the assessment is available and the number of attempts allowed, can all be varied.
Test all of my students but also Vary the order of questions to encourage them to work individually. Question libraries (e.g for NOW assessment tools) allow question order to be randomised if desired.
Create a set of questions to use and reuse across multiple assessments. Question libraries (e.g for NOW assessment tools) can be copied across a number of learning rooms. The task of creating question banks can therefore be shared across module or course teams to maximise efficiency.

There are some considerations to bear in mind, however, when planning CBA:

Applications of CBA

CBA can be used with a diagnostic, formative or summative focus:

Diagnostic assessment

CBA can be used with a diagnostic focus at the start of a course or module, or at other key points. This allows a tutor to evaluate students' baseline knowledge/understanding and, if appropriate, provide feedback. It can also be used by staff to help identify gaps in student understanding at a cohort level.

Formative assessment

CBA can be used to provide formative assessment, i.e. assessment which is developmental for students' learning but does not contribute to credit points. This can be done in-class or as directed study. CBA allows for instant feedback; this can be written to address student misconceptions directly, or to point students to relevant resources to support their own learning.

Summative assessment

CBA can be used to provide summative assessment, i.e. assessment is that which results in a final grade (and feedback) which reflects the standard of achievement of the student work against intended learning outcomes. Summative CBA may be especially useful for large cohorts, or in distance learning, where 'economies of scale' are most applicable. A broader range of scenarios can be presented than would be possible in a paper-based exam, for example by including videos and simulations. Developing assessments of this nature can take time, however.

'Exam conditions' summative assessment

Although the NOW Assessment tool can support summative assessment in exam conditions, consideration must be given to the way that any such assessment is invigilated and administered. How will you verify students' identity and prevent cheating? Are spare PCs available? Are contingency plans in place should there be a system failure? Have you considered special access arrangements (e.g. for disabled students, or those with dyslexia or visual impairments)?