Final answer:
Nielsen Media Research introduced cross-platform campaign ratings in 2013 to track audience reach over TV and digital platforms, expanding their traditional viewership measurement services.
Step-by-step explanation:
In 2013, Nielsen Media Research, a company renowned for its television and media viewership measurement launched the cross-platform campaign ratings. This innovation enables advertisers and media companies to understand the audience reach of their campaigns across both television and digital platforms. Nielsen, which carries a legacy of measuring audience sizes to influence television production decisions and advertising rates, expanded upon this expertise by incorporating cross-platform metrics. Harris Interactive, as a subsidiary of Nielsen, has also contributed to broadening their methodologies, encompassing polling data and interviews to enhance predictions for political and market trends.