I don't know of any well-validated general short scales. Here are a few thoughts:
- A major distinction is between self-report versus ability based measures. Self-report measures will ask the participant to rate their knowledge, skills, and experience. Ability based measures will require demonstration of competence. If you are limited to "self-measures", ability based measures are still possible (e.g., set of multiple choice, or possibly short answer questions). An issue with self-report measures is that people may be inaccurate in their own self-evaluation. Ability-based measures do not have this issue.
- Having more items generally increases the reliability of the test. It also permits you to assess statistically the item properties of the scale.
- Computer literacy is a broad construct. The meaning and standards of computer literacy are probably also changing over time, as computing practices change and as the computers get further integrated into society. I assume this is part of the reason why a lot of people use customised instruments. For example, I once did a study of keyboard-based text-editing. To assess prior experience, I asked a number of general questions about computing experience, but I also assessed various specific measures related to knowledge of shortcut keys.
A quick search revealed a couple of scales (e.g., Wilkinson et al, 2010, Fogarty et al, 2001). None look like entirely what you are after, but I thought I'd mention them. Both followed a formal scale development process.
Wilkinson et al
For example, here's a subset of the items from Wilkinson et al
ICT skills
I know how to create a folder
I feel confident closing down a software program
I do not feel confident attaching a file to an email
I can use a word processing application
I know how to save a document to a folder
I would not recognise a PDF (Portable Document File)
I would have difficulty finding a web site∗
I feel confident making selections from popup menus∗
I would find it difficult to search a database of references to journal papers
I need help with using computers for learninga
I feel confident using a computer to write a letter or essay
I do not know how to find an article in an e-journal
Experience with computers
I have used computers at work/school∗
I feel disadvantaged by my lack of experience with computers
I communicate with people using email
I have used computers to look for information for example: Library catalogue/books
I have used computers to support my learning
I have used computers to find out about careers
I have used computers for leisure
Fogarty et al
Here's a subset of the items from Fogarty et al
The following statements refer to your confidence when using computers.
1. I have less trouble learning how to use a computer than I do learning other things.
2. When I have difficulties using a computer I know I can handle them.
3. I am not what I would call a computer person.
4. It takes me much longer to understand how to use computers than the average person.
5. I have never felt myself able to learn how to use computers.
6. I enjoy trying new things on a computer.
7. I find having to use computers frightening.
8. I find many aspects of using computers interesting and challenging.
9. I don’t understand how some people can seem to enjoy spending so much time using
computers.
10. I have never been very excited about using computers.
11. I find using computers confusing.
12. I’m nervous that I’m not good enough with computers to be able to use them to learn
mathematics.
References
- Wilkinson, A., Roberts, J. & While, A.E. (2010). Construction of an instrument to measure student information and communication technology skills, experience and attitudes to e-learning. Computers in Human Behavior, 26, 1369-1376.
- Fogarty, G., Cretchley, P., Harman, C., Ellerton, N. & Konki, N. (2001). Validation of a questionnaire to measure mathematics confidence, computer confidence, and attitudes towards the use of technology for learning mathematics. Mathematics Education Research Journal, 13, 154-160. PDF