In case you didn’t get it the first time, or the second, or the third, there were 11 mentions of the word “transitory” in the press conference held earlier this week by Federal Reserve Chairwoman Janet Yellen.

Yellen used that word in a clear context — that tumbling oil prices won’t lead to a notable decline in inflation, and the implied future path of inflation as determined by the market may be more about a flight to safety than a meaningful change in the view of where prices are headed.

A commonly looked at measure of inflation in the market, comparing the returns on five-year Treasury inflation-protected securities with conventional Treasury securities, has dropped to 2.08%, from 2.61% as recently as August.

Here’s how Yellen described the drop in market-derived inflation measures.

“That could reflect a change in inflation expectations. But it could also reflect changes in assessment of inflation risks,” Yellen said. “The risk premium that’s necessary to compensate for inflation. That might especially have fallen if the probabilities attached to very high inflation have come down. And it can also reflect liquidity effects in markets and for example, it’s sometimes the case that — when there is a flight to safety, that flight tends to be concentrated in nominal Treasuries, and can also serve to compress that spread. So I think the jury is out about exactly how to interpret that downward move in inflation compensation.”

In a note to clients, Gustavo Reis, an economist at Bank of America, took a look at the phenomenon, not just in the U.S. but in the euro area and the U.K. as well.

Regressing the data, he didn’t see a significant effect from either oil prices or data surprises.

“Higher volatility seems to be weighing on the euro area measure, but not abnormally so. In other words, short-term factors do not seem to be driving the decline in long-term inflation expectations. This leaves open the possibility of a genuine slide in expectations,” Reis said.

He also found there was something to what Yellen said about the probabilities of very high inflation coming down. In the U.S., there are now virtually no bets on inflation being over 3% in five years time.

“This suggests that much of the action in market-based expectations has indeed been driven by tail risks,” he said.