The latest study conducted to examine the test-retest reliability on adherence with inhaled corticosteroids in adults with asthma using a self-reported adherence score (Foster score) found that there is a poor agreement with the objective measures of adherence. The study by a group of researchers from the Department of Respiratory Diseases, Aalborg University Hospital, Denmark, published in Journal of Asthma and Allergy, concluded that while foster score shows an excellent intraclass correlation coefficient (ICC), it should not be used by clinicians to assess the adherence with inhaled corticosteroids in asthma patients. Foster score is a self-reported adherence score whereby the patient is simply asked the question of the number of days they take their medicine in a week, which has a poor agreement with the objective measures of adherence and thereby there is a need for a reliable method of measurement in order to assess the drug adherence in asthma patients.