1. A computer-readable recording medium that stores a computer program for predicting, based on accumulation data in which a correlation between a combination of attribute values and a result of the combination is accumulated, a result,of assessment target data including a new combination of the attribute values, wherein the computer program causes a computer to execute: structuring including combining an attribute value of the assessment target data with an attribute value indicating a unspecified value; and generating a combination pattern of the attribute values; reconstructing including searching data matching the combination pattern from the accumulation data; and generating subset data; setting an index indicating significance of relationship between the generated subset data with assessment data; and assessing including selecting subset data that becomes a basis of assessment, based on the set index; and performing an assessment on a prediction result based on the selected subset data.