In Opinion No. 28, the APB stated that interim financial information is es- sential to provide timely data on the progress of the enterprise and that the usefulness of the data rests on its relationship to annual reports. Accordingly, the Board determined that interim periods should be viewed as integral parts of the annual period and that the principles and practices followed in the annual period should be followed in the interim period. However, certain modifications were deemed necessary to provide a better relationship to the annual period.