When a publicity campaign is planned, it is necessary to very consider the number and the type of people to whom we wished to hit. In order to secure that information control means exist that contribute the wished data to us. Between the main ones we can emphasize:

• OJD. It has as an aim giving to know the distance and diffusion different means written. Due to interpretation problems, some journalistic companies have chosen to control their distances through notaries or companies auditors. In any case, it is continued valuing positively.
• EGM. It facilitates the profile of the person of each one of the means (presses, magazines, radio and television), as well as the levels of hearing that they have. For year 2008 it has predicted to modify his model of management doing it more flexible.
• Taylor Nelson Sofres (TNS). Company in charge to facilitate the data of television hearing. It acts as notary and it signs the act of the daily televising consumption, combining computer science with the sociological survey, through the audímetros installed in the sample of Spanish homes.
• Nielsen/NetRatings. Company specialized in the measurement of hearings in Internet, has started up a service of public certification of hearings by which it will justify in open the data of traffic measured in each Web site. The objective of this program of certification of hearings of Nielsen/NetRatings is to provide a public summary of level of hearing of the sites measured with its censal tool Country Market Intelligence Spain and, simultaneously, to facilitate the access to these initial datas as much to clients as to other organizations or interested organizations.