Table of Contents
We all know education matters: it increases health, longevity, and income.
And, with just common sense, we know that teacher quality matters: students learn more with better teachers.
Most people, however, are unaware of just how much teacher quality matters.
Teacher Quality Matters
If you replace an average teacher in just one subject with a teacher that is 3 standard deviations higher in quality (so a 50th percentile teacher with roughly a top 1% teacher), the earnings of the students in that class will have, on average, 3.9% higher incomes (at the age of 28, which is when the study measured until).
That is stunning.
Over a lifetime, that could easily be tens of thousands of dollars in extra earnings because of one teacher.
Teacher Quality
Teacher quality was measured and defined by the impact that a teacher had on their students’ standardized test scores. (So, if a teacher’s students had larger increases in standardized test scores than 99% of other teachers, that teacher would be a top 1% teacher in this study).
But how did teachers actually affect those standardized test scores? The study didn’t look into that, but a teacher’s effect on a given student’s test scores fades over time and yet the increase to earnings remained. So a student could have a top 1% teacher, see their standardized test scores rise more than 99% of other students (this doesn’t mean they got top 1% standardized test scores, only that they saw top 1% larger improvements to their scores), lose that increase to their standardized test scores in later years, but still retain the increase in earnings later.
How does that make sense?
Top Teachers
So what sticks with students if it’s not a permanent increase to their standardized testing percentiles? Likely more than just the additional knowledge they learned.
Top teachers don’t just teach academic knowledge and skills. They teach life skills. They teach that you should push yourself, that you should fail (if you’re not, you’re clearly not pushing yourself to the limits of your ability), that you can get back up, that you can persevere, that you have far more control over your life and your destiny than most people believe, that hard work pays off, that curiosity is key, that hope is necessary for progress, that fair and respectful competition can bring out the best in us and lead to innovation, that honesty and integrity are paramount because trust lost can often never be regained, that people are more important than things, and that the best investment you can make for your own success is to improve yourself.
The latter will and will not show up on a standardized test. It will show up on a standardized test in the sense that a student is more likely to work hard and succeed academically if they have the right mindset. And, yet, even if they lose the knowledge and skill to outcompete their peers on standardized tests, if they retain the knowledge and skill of how to succeed in life, that’s more valuable. That’s how just one top teacher can very significantly improve the outcomes of a student, even if we just measure the financial outcomes of that student.
You
You are your best investment. More than any other person, you control your health, your happiness, your success, and your fate. But you don’t need to do everything all at once.
In 2003, Dave Brailsford stepped in as the performance director for British Cycling, a sport that had spent over a century in mediocrity. Things were so bad that one bike manufacturer even refused to sell to British cyclists, worried that their consistently poor results would hurt the brand’s image. But in just five years, Brailsford led a remarkable transformation, turning British Cycling into a powerhouse at the 2008 Olympic Games. So, how did he pull it off? His approach was simple but powerful: the philosophy of “the aggregation of marginal gains.” By making 1% improvements in everything — from training routines to bike equipment — Brailsford showed that small, consistent changes could lead to massive overall success.
Rome wasn’t built in a day. You won’t build yourself in a day either. Just focus on getting better. When you fail at that, try again. When you fail again, keep trying. You will succeed. And, if you need help in a subject or an area of your life, enlist the help of a top teacher or top mentor. They can have a lasting impact.
