--- title: "Focus" slug: "focus-syntax" updated: 2022-07-27T22:26:35Z published: 2022-07-27T22:26:35Z canonical: "code.tag.bio/focus-syntax" --- > ## Documentation Index > Fetch the complete documentation index at: https://code.tag.bio/llms.txt > Use this file to discover all available pages before exploring further. # focus ## focus **usage: *common* - datatype: *object*** The *focus* for a Tag.script is the intersection of the *background* attribute and the set of entities defined by the *focus* attribute. The *focus* attribute is mandatory when the analysis method is "tag-comparison". There is no default value for the *focus* attribute, therefore an error will be thrown if it is undefined for a "tag-comparison" analysis. The simple form of the *focus* attribute is a single categorical variable object. ``` "focus": { "variable_type": "categorical", //A categorical variable object "collection": "cccc", //"cccc" is a valid categorical collection name in tag.cortex "variable": "vvvv" //"vvvv" is a valid variable name in collection "cccc" } ``` Alternatively, the *focus* attribute can be any categorical variable object that compiles to a single categorical variable, e.g. "categorical-compound". ``` "focus": { "variable_type": "categorical-compound", "operator": "oooo", //"AND" for intersection, "OR" for union "criteria": [ {...}, //Two or more categorical variable objects {...}, ... ] } ```