Home › Morkes and Nielsen Example › Morkes and Nielsen Example (True Sections) › Concise, SCANNABLE, and Objective: How to Write for the Web › Study 3: Measurement Study

Normalized Scores and Overall Usability Scores

To determine how much better or worse in percentage terms each site version was relative to the control, we normalized all participant groups' mean scores for the 5 major measures. For each measure, the control condition's mean score was set to equal 100, and the other conditions' mean scores were transformed (by division) relative to the control (see Table 2). Scores above 100 are "better" than the control, and those below 100 are "worse."

Next, we calculated an Overall Usability score for each version of the site, by taking the geometric mean of the normalized scores for the 5 measures (the geometric, rather than arithmetic, mean was used because we compared ratios). Again, the control version's score was 100.

Version Task Time Task Errors Memory Sitemap Time Subjective Satisfaction Overall Usability
Promotional (control) 100 100 100 100 100 100
Concise 172 205 142 124 156 158
Scannable 157 273 94 130 133 147
Objective 128 164 116 121 112 127
Combined 242 818 162 142 122 224

Table 2. Normalized mean scores for five major measures and Overall Usability. Scores above 100 (the control score) are "better." For example, the scannable version is 57% better than the control for Task Time.

Comments

Post new comment

The content of this field is kept private and will not be shown publicly.
  • Lines and paragraphs break automatically.

More information about formatting options

Type the characters you see in this picture. (verify using audio)
Type the characters you see in the picture above; if you can't read them, submit the form and a new image will be generated. Not case sensitive.