A designated market area (DMA) is a group of counties or a group of county equivalents (such as parishes) that share common, localized, market conditions. A DMA is usually defined by Nielsen Media Research, in large part using Metropolitan Statistical Areas (MSAs) which are identified by the US Census Bureau.

Nielsen, a global measurement and data analytics company, measures local television viewing by monitoring the habits of a sample of households in each DMA. The data collected is then used to extrapolate the viewing habits of the entire market, providing valuable insights into the preferences and behaviors of viewers in specific areas.

The DMA system was developed by Nielsen to provide advertisers and CMOs with a standardized way of identifying and targeting specific television markets across the United States. The system has become a vital tool for marketers, as it enables them to create targeted campaigns that are tailored to the unique needs and characteristics of each DMA.

The DMA system has several advantages for advertisers and CMOs. First, it allows them to measure and compare television viewing habits across markets, enabling them to identify the most popular programs and channels in each DMA. This information can be used to make more informed decisions about where to allocate advertising budgets and which channels to target.

Second, the DMA system enables marketers to tailor their messages to specific audiences. By understanding the unique characteristics and preferences of each market, they can create campaigns that resonate with viewers in each DMA. This can help to increase engagement and drive conversions, leading to improved ROI on marketing investments.

Finally, the DMA system provides advertisers and CMOs with a way to measure the effectiveness of their campaigns. By monitoring viewership data before and after a campaign, marketers can determine the impact of their initiatives on local audiences.

In conclusion, the DMA system is an essential tool for advertisers and CMOs looking to develop targeted campaigns that reach specific audiences. By providing insights into the unique characteristics and preferences of each market, the DMA system helps marketers to create campaigns that resonate with viewers, increase engagement and drive conversions. As the media landscape continues to evolve, the DMA system will remain a critical tool for marketers seeking to optimize their advertising investments and reach audiences in new and innovative ways.