A baseline is a starting point used for making comparisons or measurements. In science experiments, researchers establish a baseline by measuring conditions before making any changes. For instance, if you wanted to test whether a new study method improves your test scores, your baseline would be your average score before trying the new method. Without that baseline, you couldn't tell if the new method actually helped.

In medicine, doctors often check baseline measurements like blood pressure or weight during regular checkups. These baselines help them notice changes over time. If your baseline blood pressure is normal but suddenly spikes at a later visit, that signals something worth investigating.

Athletes use baselines too. A basketball player might record baseline statistics for free throws made, assists, or rebounds at the start of the season. Throughout the year, coaches compare current performance against those baselines to track improvement or identify problems.

Tennis courts and baseball fields also have physical baselines that mark boundaries.

Whether measuring academic progress, health, or athletic performance, a baseline gives you something solid to measure against. It answers the essential question: “Compared to what?”