The formal S4 class for SGP. This class stores the data object for use with the functions analyzeSGP, combineSGP, summarizeSGP, and visualizeSGP. The SGP class contains and organizes all the results associated with SGP analyses. is.SGP tests for membership for this class.


Objects can be created by calls of the form new("SGP", ...), but this is not encouraged. To instantiate a new instance of SGP class use the function prepareSGP instead. is.SGP(x)



A data.table including student-level data in a (long) format. For annual testing, each VALID_CASE, CONTENT_AREA, YEAR, ID combination represents a unique case in the data. For instances with multiple tests within a year, each VALID_CASE, CONTENT_AREA, YEAR, ID, WITHIN_YEAR combination represents a unique case in the data. See sgpData_LONG for an exemplar data set


A list (possibly NULL) providing additional data.tables containing student level multiple-membership lookup tables. For example, sgpData_INSTRUCTOR_NUMBER provides student teacher linkages and can be embedded in this slot using a list that contains it.


A data.frame with five columns: 'names.provided', 'names.sgp', 'names.type', '', 'names.output'. This data.frame is used as a lookup table to translate state specific variable names to SGP variable names as well as provide information for summarizeSGP on the types of summary tables to produce.


A list including the output from analyzeSGP


A list including the output from summarizeSGP


A list of meta-data including the version of the SGP package used to construct the SGP object and the date the object was created.



combines class list and class NULL

See also