Yellen's positive outlook on the U.S. fiscal situation, including manageable debt levels and efforts towards deficit reduction, can be seen as supportive of economic stability. This stability is crucial for investor confidence, which in turn can positively affect the stock market, including broad market ETFs like SPY. The relevance is high as the health of the U.S. economy directly impacts market sentiment, though not at the maximum since the comments are more general and not SPY-specific. The importance is moderate because fiscal health is a key factor in market performance, but other factors also play significant roles. Confidence in this analysis is high due to the direct relationship between economic indicators and market performance.