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A Study of the Effect of Thumb Sizes on Mobile Phone Texting Satisfaction

Vimala Balakrishnan and Paul, H.P. Yeow

Journal of Usability Studies, Volume 3, Issue 3, May 2008, pp. 118-128

Article Contents


Statistical Package for the Social Sciences (SPSS) 13.0 software was used to test the statistical effect of thumb length and circumferences on users' texting satisfaction based on keypad design factors. Analysis of covariance (ANCOVA) and Pearson correlations were used to analyze the collected data. All results are considered significant at p < 0.05 level.

Table 3. ANCOVA test for keypad design factors satisfaction, based on thumb circumference and length
Keypad design factors Thumb circumference
F-ratio (p-value)
Thumb length
F-ratio (p-value)
Size 11.411 (0.001*) 3.111 (0.079)
Simplicity 0.189 (0.665) 3.255 (0.074)
Space 8.608 (0.004*) 3.989 (0.059)
Shape 0.046 (0.831) 1.956 (0.165)
Layout 2.439 (0.121) 4.235 (0.042*)
Texture 0.696 (0.406) 3.123 (0.080)

*: significant at p < 0.05

In Table 3, significant main effects of thumb circumference were observed for users' satisfaction towards key size and space between keys. A significant correlation was found between thumb circumference and key size (p = 0.001, r = -0.309) and with space between keys (p = 0.004, r = -0.272). The main effect of thumb length was found to be significant for keypad layout, both significantly correlated to each other (p = 0.042, r = -0.194).

Table 4. Pearson correlations between thumb measurements and texting satisfaction
Thumb measurements p-value r
Thumb circumference <0.001* -0.628
Thumb length 0.057 -0.201

*: significant at p < 0.05

Table 4 shows the correlations between the thumb measurements and the dependent variable, texting satisfaction. A significant negative correlation was observed between thumb circumference and users' texting satisfaction (p = 0.003). No significant correlation was found between thumb length and users' texting satisfaction.

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