There is a direct correlation between the size of advertising agencies, the services they offer, and the benefits those services provide to the client company. Small advertising agencies may only offer regional services and may not reach a broad audience, while large advertising agencies can provide services on a national and international scale, reaching very wide audiences. This is because small advertising agencies may lack the resources to conduct extensive pre-market research necessary for certain services, resulting in suboptimal effectiveness even if they attempt to perform the research.

Large agencies utilize various sources in the advertising preparation process, including street surveys and reports from market research companies. The data obtained from these sources undergoes strategic planning before it reaches the creative design team. This team prepares the copy or slogans that will outline the advertisement. The graphic design team enhances the advertisement visually, making it more eye-catching. After this stage, a department oversees production. Here, printing and manufacturing companies, such as digital printing, signage, and commercial printing firms, create the tangible materials for the advertisement. Additionally, preparing a report on the feedback obtained from these advertising campaigns is part of the advertising agency's reporting responsibilities.