Utilize the input text as a context reference, choose the right relationship between Janet Yellen and economist from the options. Options: product/material produced, manufacturer, distributed by, industry, position held, original broadcaster, owned by, founded by, distribution format, headquarters location, stock exchange, currency, parent organization, chief executive officer, director/manager, owner of, operator, member of, employer, chairperson, platform, subsidiary, legal form, publisher, developer, brand, business division, location of formation, creator.

NEW YORK ( TheStreet ) -- Federal Reserve Chair Janet Yellen made it as clear as an economist can on Friday that interest rates will begin rising this year.

Answer: position_held