Westwood’s MarketShare has purchased fellow marketing attribution company DataSong of San Francisco for an undisclosed amount. With the purchase, MarketShare will integrate DataSong’s software into its own, expand its employee count by 50 and grow its number of retail customers.

Using a statistical method called regression analysis, MarketShare and DataSong’s cloud-based software programs try to correlate sales to money spent on promotions like television advertisements, online banner and print advertisements, events and social media posts.

The exploding number of online and offline advertising options has made it more difficult for marketers to determine which are most cost-effective. In the past, some hired consultants to analyze their marketing efforts by hand, but that was costly and time consuming. Cloud-based software programs like MarketShare’s promise to inexpensively automate the process, while adding faster feedback.

MarketShare claims its program’s recommendations typically improve marketing effectiveness by 20 to 30 percent and increase revenue by 3 to 4 percent.

In DataSong, MarketShare picks up a business focused on marketing attribution technology, which tracks each time a customer sees a retailer’s promotion and paints a picture of the path a customer takes before purchasing an item.

DataSong’s 50 employees will remain in San Francisco. The company’s chief executive, John Wallace, will become MarketShare’s chief growth officer. DataSong President Mike DeVries will become head of business management.