In the 21^st Century, the ability to synthesize multiple sources of information will determine workforce capabilities and ultimately the quality of lives. Most present day instructional practices, however, aim at reading and understanding single texts. This may be due to the lack of assessment measures that list the criteria for synthesis of multiple texts.

In response, I created the rubric, Guide to Rating Synthesis of Multiple Texts (GRSMT). In this study, I set out to determine whether the guide I created measures synthesis of multiple texts and if the scores derived are reliable. I determined that the GRSMT rubric measures synthesis of multiple texts by asking experts in the field of literacy. The experts who responded to my survey agreed the rubric measures the skills associated with synthesis of multiple texts, thereby establishing content validity.

I determined the scores derived from using the rubric are reliable by establishing internal consistency and inter-rater reliability using Cronbach's alpha and Cohen's Kappa. The results revealed excellent internal consistency and established the scale as unidimensional. Inter-rater reliability results indicated the guide needs improvements such as additional score points that indicate a lack of synthesis and the descriptors need better examples. The study findings provide support for improving the GRSMT to obtain reliable and valid scores that indicate a student's ability to synthesize information across texts.

This study increases reading research's knowledge base by operationally defining synthesis of multiple texts and developing an accessible and facile measurement rubric. A potential contribution of this study is its influence on evaluation practices that indicate student ability to synthesis information from multiple texts and consequently its influence on instruction that promotes synthesis of multiple texts. This is important because 21^st Century learners must develop the ability to synthesize across multiple, disparate text to survive complex, present day and future academic and work place demands, Equipped with a definition and a rubric that explicitly delineates criteria needed for success, researchers and teachers may be better able to design instruction that teaches students the skills and strategies that help them become proficient synthesizers of multiple texts.