A questionnaire Usability Self Learning Module is developed to measure the overall
development of the learning module Adobe Photoshop constructs involving three modules, module’s
usability, applying theory of the cognitive load and minimalist. The study was conducted to produce
empirical data on the reliability and validity of the Usability of Adobe Photoshop’s Module
questionnaire using the Rasch Measurement Model. A survey was conducted on 120 participants who
attended the course Adobe Photoshop using the modules studied. The questionnaire is distributed
using one of the Web 2.0 technology platform, Google Docs. The reliability and validity of the
Usability Adobe Photoshop’s module questionnaire were tested with the Rasch Measurement Model
using the Winstep version 3.69.1.11 program.The Rasch analysis showed that person reliability index
is 0.87 and item reliability of 0.94. In term of item polarity, each item was able to contribute to
measuring the effectiveness of the learning module development measurement since the PTMEA
CORR exceeded 0.30, in specific between 0.50 to 0.78. There are 27 items in the questionnaire, which
is divided into 3 different constructs. Each construct contains 7 to 11 items. The unidimensionality test
conducted showed standardized residuals variance of 49.8%, with the biggest secondary dimension
in the first constrast amounting variance of 6.5%. Item fit analysis showed that none of the items
needed to be dropped since infit mean square values are between 0.73 and 1.39, and the outfit mean
square values are between 0.70 and 1.40. Items in the questionnaires are ordered in a continuum of
increasing intensity for the measurement of the Usability of Module construct. This shows the validity
of the constructs in Usability of the module.The Rasch Measurement Model shows that the Usability
of the Module has a high reliability and validity to be used for measuring the usability of the module
and the application of cognitive load theory and the theory of minimalism