Russell Colley in the year of 1961,while proposed this advertising model said that an effective advertising strategy seeks to communicate more rather than to sell. Advertisers always focuses on the fact that the exact message which they want to convey for making the people aware of the particular product, mission or company, must be comprehended by the similar way. 
With the help of this model, the advertisers target their respective audiences to provide them with the real understandings and motive about the particular product launch by informing about the respective benefits . 

DAGMAR in other words can be termed as an efficient marketing expression which also acts as a tool to compute the outcome of any advertising campaign. 
It stands for -
D - Defining
A - Advertising
G - Goals for
M - Measured
A - Advertising
R - Results. 
Further this model goes through the primary four stages which defines the actual understanding of this advertising expression. 
  • Awareness
  • Comprehension
  • Conviction
  • Action
The first one i.e. Awareness about the newly launched product or any kind of services is the vital for the both the company/services and customers. Awareness has to be created, developed, refined and maintain according to the characteristics of the market and scenario of the organisation at any given point of time. Then comes the second stage of Comprehension because only awareness is not efficient for creating an urge among the consumers. So it's necessary to put an answer for the common consumer worries that why to purchase the specific products or how it's different from the other prevailing brands of the same product. So this stage aims to provide people all the required information about the product. Comprehension is followed by the stage of Conviction where the main task of advertising company is to mould the target consumers beliefs by persuade them to purchase the product even it does this by flaunting the rewards or incentives for using the product. Then comes the most important and final stage  i.e. Action where the customers after being mould their opinion positive, make themselves ready for the final purchase by implementing the optimistic views for using the product.