Common Core turned out to be a big flop as it resulted in lower academic performance and declining student achievement since its inception in 2009, during the Barack Obama days. The former president wasn't responsible for creating the Common Core disaster, but he didn't stop it either, and that's part of the reason that so many people were affected and constantly bashing the practice.

I taught public school for 15 years and can agree, that Common Core was the worst thing ever forced upon a child. When you take 12 extra steps to answer a simple question, that's called setting kids up for failure and giving them more opportunities to make mistakes. I'll be the first to tell you that anytime I was told to teach to the common core, that I automatically threw that lesson plan in the trash and taught my students the right way. Common Core is a joke and everyone from parents, students, teachers, and even principals dislike it. What the heck, even the lunch lady hates it.

A simple question like 5+4 doesn't need to turn into a 12 step process to get the answer of 9.

It was refreshing to see some real research being done on the failure known as Common Core - and if there's one thing people wished Obama had done, it was step in and get rid of that absurd failure. We don't need to reinvent the wheel.

The research done to prove Common Core was a failure that showed declining student achievement was conducted and published by the Pioneer Institute.

Here's a tidbit from their research, which goes a lot further in depth.

The authors find that after several decades of only incremental test score improvements, which started prior to federal requirements for curriculum centralization, since Common Core was implemented in 45 states and Washington, D.C., student results are showing the first significant declines in achievement, especially for students who were already behind.
Fourth- and eighth-grade math scores were down overall on the 2015 and 2017 National Assessment of Educational Progress. The declines among lower-performing students (bottom quartile) were even steeper. Fourth- and eighth-grade reading scores were flat, with declines among lower-performing students. At the same time, the U.S. is no closer to the internationally competitive performance in math and science observed in top-tier developed nations.
Instead of accelerating the curriculum to more advanced topics and following the practices of leading international competitors, Common Core’s politically-driven process resulted in the adoption of the mediocre curriculum sequences used in a number of mid-performing states and promoted progressive instructional dogmas shared by its developers.

Myself and other teachers knew Common Core was a joke and now we have years of fact based evidence to back up our claims. We knew Common Core was a failure from the moment someone tried to teach a math expert a new way to solve a problem and they added like 20 extra steps that were completely unnecessary.

Good teachers ignore Common Core and teach the way that things were meant to be, the way that things make sense, and the way that students understand in the easiest way possible. We've made it this far without Common Core, I think we can keep going.

The "Pioneer Institute is an independent, non-partisan, privately funded research organization that seeks to improve the quality of life in Massachusetts through civic discourse and intellectually rigorous, data-driven public policy solutions based on free market principles, individual liberty and responsibility, and the ideal of effective, limited and accountable government."

Source: pioneerinstitute,