A U.S. Supreme Court justice once famously used that phrase to dismiss the challenge of defining pornography. For parents without formal training in education, the challenge of defining good teaching is even more daunting.

The research is clear: nothing has a bigger impact on student performance than the quality of instruction and the quality of the teacher leading students in the classroom. But for too many parents, it is difficult – if not impossible – to distinguish between the varying teaching techniques and styles to make informed judgments regarding their relative effectiveness.

But a new tool can help.

The Hechinger Institute at Columbia University, and the Los Angeles-based Cotsen Family Foundation have developed a website on what to look for in the classroom. Although specifically designed to help journalists do a better job of covering education, the material on the website, including video examples of effective teaching and supporting commentary, can be equally informative for parents.

Invest a little time with these tools! Then when you look for quality teaching in your child’s classroom, you just might know it when you see it.