This study describes the characteristics of instruments mentioned in the literature for calculating the disclosure index of accounting information. Descriptive research was conducted through document analysis with a qualitative approach. The results focus on five themes which express the care needed to develop a metric to measure the accounting information disclosure: target audience and definition of coercive and voluntary information; the choice of the database; extension of the data collection instrument; factors that interfere with the metric; and reliability testing. The study may contribute in identifying metrics for measure the extent of the accounting information disclosure by companies.