Choosing a reliable parental control tool is essential to supervising minors accessing information and using electronic devices. For this, it is necessary to determine which tools are the most suitable and if their functionalities are effective. To our knowledge, despite the availability of existing tools that evaluate applications and different actors, e.g., parent control applications recommended by Internet Service Providers (ISPs), none of them properly characterize the various functionalities provided by the application while validating their efficacy. In this paper, we propose a new comprehensive metric to effectively identify and evaluate the functionalities provided by tools in the field of parental control. The metric is applied to some of the most downloaded apps from the Play Store, and the results are compared with the applications recommended by ISPs in Chile, which cover more than 93% of the market. The results from our analysis show that none of the parent control applications recommended by Chilean ISPs managed to provide full confidence in the functionalities implemented since at least one of their functions did not pass the test applied. The end goal for the test metric proposed is to allow future developers to assess their applications beforehand while offering a better match with the customer's expected service.