The last essential issue in the characterization of design as a sales tool is the problem of assessing its effectiveness. The peculiarity of design is that this phenomenon is very subjective, so it is impossible to give an unambiguous assessment, clearly expressed in numbers. For example, the degree of influence of corporate identity on the consciousness of the target audience is almost impossible to calculate. Theoretically, some idea of this can be obtained through a consumer survey. However, the survey will work only if the company uses its corporate identity for several years, and actively uses it in television and print advertising.
And yet, if we abstract from the problems of corporate identity, it is easy to understand that the effectiveness of some types of design can and should be controlled. For example, websites, for example, lend themselves well to control. Traffic and behavior of visitors to the resource can easily track even a layman. Draw conclusions from this analysis and make appropriate changes to the site is also quite realistic. The effectiveness of print advertising is also amenable to some measurement. You can always ask customers and find out how many of them came because they were interested in the information on the flyer or billboard.
In general it can be concluded that the effectiveness of design, inextricably linked with a particular advertising medium, it is possible to calculate. The main thing to understand that in addition to the design itself, the advertising message should be quite attractive. And the success or failure of a particular type of advertising can not be explained by any one factor.