A Communist in her youth, she moved to Moscow in 1950 with her husband Joseph Clark, foreign editor for the Daily Worker; they became disillusioned with the Soviet regime and returned to the United States in 1953.
In 1960 she was hired by Louis Harris' firm, working for John F. Kennedy campaign.
Clark was credited to introducing exit polls in American election surveys.
Clark, vice-president at Yankelovich, Skelly & White, conducted a survey with 120 readers in a dozen focal groups;[4] the readers said they felt alienated by the newspapers' focus on hard national, political news, they wanted more palatable local news stories and everyday tips.
The report influenced newspapers in the United States and around the world; its findings translated into innovations in news coverage, like the increased focus on local stories, "news you can use" and the modular layout of pages, which were adopted by several outlets, especially USA Today.