The Globe and Mail reports in its Tuesday edition that bonds are meant to be a safe investment and, traditionally, when stock markets dive, bonds are supposed to rise. Guest columnist Bryce Leung writes, however, that didn't happen in 2022. Bonds move in the opposite direction of interest rates. This is because rising interest rates mean that new bonds being issued will pay a higher rate than existing bonds, which makes those existing bonds comparatively less attractive. This is when bond duration becomes important. Duration is a measure of how sensitive a bond fund is to interest rate changes, and is usually published in a fund's prospectus. For example, the iShares Core Canadian Universe Bond Index ETF (XBB) currently has a duration of 6.7. This means that if bond yields rise 1 per cent, XBB can be expected to fall in price by around 6.7 per cent. That's why in a rising-interest-rate environment, it makes sense to shorten the duration of your bond holdings by using a short-term bond fund like the iShares Core Canadian Short Term Bond Index ETF (XSB), which has a duration of just 2.8. This way, if yields rise 1 per cent, XSB will fall by around 2.8 per cent.