Thurstone Scale

Thurstone Scale

Thurstone was one of the first and most productive scaling theorists. This scale is associated with LL Thusrtone, so this scale is known as Thurstone scale. During the 1920, Thurstone and his co-workers attempted to measure attitude on an interval measurement scale, on which equal differences in scale values correspond to equal differences in attitude strengths by using the methods pair comparisons and equal appearing intervals.

This technique assesses the extent of agreement among a group of judges about the content validity of proposed items for a scale.

Purposes
The scale is used to measure attitudes-toward any school subject, vocation, institution, defined group, proposed social action, practice, home making activity as well as individual and group morale and the high school.

Structure
There are about 200 statements expressing attitudes toward something
The scale has 11 categories by a large sample of judges.
This categories range from least favorable (category 1) to most favorable (category 11).
The judges are instructed to think of the 11 categories as lying at equal intervals along a continuum.
After all judges have completed the shorting process for all statements, a frequency distribution is constructed for each statement by counting the number of judges who placed the statement in each category.
Next, the median and semi-interquertile range for each statement are counted from the corresponding frequency distribution.
Then the statements are rank ordered according to there scale values and 20 or so statements are selected for the finished scale.

Advantages
The Thurstone type scale constitutes a reasonably satisfactory ordinal scale.
The Thurstone method has been widely used for developing differential scales which are utilized to measure attitudes
Such scales are considered most appropriate and reliable when used for measuring a single attitude.

Disadvantages
The use of the scale is costly and need effort required to develop them.
The values assigned to various statements by the judges may reflect their own attitudes.
Some other scale designs give more information about the respondents’ attitudes in comparisons to differential scales.