Software Engineering

Appendix to Report #1: SYSTEM SPECIFICATION

Report #1 -- Appendix A: User Effort Estimation

"User-interface navigation" refers to the mouse clicks or keystrokes needed to navigate through different windows of the user interface until you reach the appropriate context where you can enter the data. ("Context" roughly corresponds to the window in which the data entry will take place.)

"Clerical data entry" refers to the mouse clicks or keystrokes needed to enter data into your system, once you're already in the appropriate context (the window that you reached by navigation).

Consider the following example: setting the page margins in Microsoft Word so that the top margin equals 0.5in, bottom = 0.7in, left = 1.25in, and right = 2in.

Assume that the document is currently open. What you need to do is (1) to navigate to the appropriate context, and then (2) enter the data that specifies the desired margins.

  1. NAVIGATION: total 3 mouse clicks, as follows
    1. Click "File" menu
    2. Click "Page Setup..." menu choice
      --- after completing data entry as shown below ---
    3. Click "OK" button to finish (i.e., to leave the current context and get back to where you started from)
  2. DATA ENTRY: total 1 mouse click and 12 keystrokes, as follows
    1. Click cursor to "Margins/Top" text field
    2. Press the keys "." and "5"
    3. Press the "Tab" key to move to the next text field ("Bottom")
    4. Press the keys "." and "7"
    5. Press the "Tab" key to move to the next text field ("Left")
    6. Press the keys "1", ".", "2" and "5"
    7. Press the "Tab" key to move to the next text field ("Right")
    8. Press the key "2"
Note: Instead of clicking the "OK" button in Navigation, alternatively you could have just pressed the "Enter" key to finish. Hence, the distinction between NAVIGATION vs. DATA-ENTRY is not always straightforward, but just do your best -- this is an estimate anyway.

Additional Information

The above method for user effort estimation is very basic and probably not very useful in real-world projects. For more sophisticated methods, check the following sources:

GOMS at Wikipedia, the free encyclopedia

Methods: GOMS (Goals, Operators, Methods, and Selection Rules)

GOMS Tutorial — provides a summary of the GOMS method extracted from:
David Kieras, A Guide to GOMS Task Analysis, University of Michigan Technical Report, Spring 1994.

Fitts' law at Wikipedia, the free encyclopedia

Hick's law at Wikipedia, the free encyclopedia

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Ivan Marsic
Mon Feb 12 15:33:38 EST 2007