The effect size was

You usually follow this phrase with a descriptor or a number. You might say The effect size was large or The effect size was 0.5. It almost always appears when you are summarizing data. You can use it to compare two different things, like two teaching methods. It helps your audience visualize the magnitude of your discovery. Think of it as the difference between saying "it's hot" and "it's 100 degrees." It adds precision to your claims. You’ll sound like a data-savvy pro when you use it correctly.

Use this in any professional or academic setting involving data. It’s perfect for university essays, lab reports, or business presentations. If you are a marketer showing how a campaign worked, use it. If you are a doctor discussing a new treatment, use it. It’s the gold standard for reporting results in the 21st century. It shows you aren't just looking at surface-level numbers. You are looking at the actual weight of the evidence. It’s a very impressive phrase in a boardroom or a classroom.

Avoid this phrase in casual, everyday conversations with friends. If you say The effect size was small regarding a movie you watched, you’ll sound like a robot. It’s too clinical for emotional or social situations. Don't use it when you are guessing or being vague. It implies you have actually measured something. Using it without data makes you look like you’re trying too hard to sound smart. Keep it away from your dating life or your pizza orders. It’s a tool for analysis, not for small talk.

This phrase rose to fame because of the "replication crisis" in science. For years, researchers only cared about "p-values," which just say if a result is a fluke. But people realized that tiny, useless results were being called "significant." The scientific community shifted toward effect size to ensure honesty. It represents a cultural move toward transparency and practical value in research. It’s now a mandatory part of reporting in psychology, medicine, and social sciences. It’s the "show me the money" of the academic world.

You might hear people say The magnitude of the effect. In specific circles, they might say The Cohen’s d was... which is a type of effect size. Some might simply say The impact was substantial. However, The effect size was remains the most formal and standard way to start the sentence. It signals to your reader that a serious statistical explanation is coming next. It’s a classic "researcher" sentence starter.