The purpose of this study was to develop the Student Knowledge Linking Instrument (SKLI), an inventory for middle grades students that seeks to understand student knowledge construction processes. This study included 461 fifth and sixth grade students and follows from a series of qualitative studies that were used as a foundation for development of the SKLI. The SKLI captures student knowledge linking through student responses to brief reading passages and is proposed to capture the students' situation definition (Wertsch, 1985), specifically their initial links with the information. Eight student linking profiles emerged from these students' data, with students on one end of the spectrum drawing on surface characteristics of the text in their linking, while others used more elaborative links that indicated a depth of processing. These profiles were hypothesized to be developmentally ordered, supported by an increase in elaborative links for some sixth grade students in this group.