More companies across the U.S. are experimenting with a truncated workweek as employees demand flexibility and studies show that actually working less can make people more productive while boosting a company's profits. Online consignment and thrift store ThredUp, a public company with 300 corporate employees, has made the shift to four days permanent after a successful one-year experiment. Co-founder and CEO James Reinhart told CBS MoneyWatch that the shorter workweek has improved employee morale and increased productivity.

How did this experiment come about in the first place? What was wrong with working five days a week?

James Reinhart: The catalyzing event was at the onset of the pandemic in April 2020 when many companies were laying off large swaths of workers. We said, 'Let's experiment with 80% pay for four days of work a week. It forced this experiment in service of our balance sheet. We did that for a year. People were paid 20% less, and their experience was, 'I get just as much done, I'm happier, I can spend more time with family and be more creative.'

In 2021, we kept the four-day schedule and switched everyone to full-time pay. At the time, I said it was an experiment and we would measure the impact and hold ourselves accountable. Now we're two-plus years into it. 

Sounds like the experiment was a success. What made it work?

JR: I've always believed happy employees are great employees. So if you can find an opportunity to make people really love their work and company, so they come to work happy, they create better companies.

Early in our life as a company [before the pandemic] we had work-from-home days, you could qualify for a sabbatical after being at ThredUp for just a few years, so we had built a culture where employee well-being was a key input to retention and productivity.

What are the fundamental changes you made to allow for this shift?

The quantitative, rigorous approach is you have to get five days of work done in four days. That means you need to work harder and be more efficient with your time on four days. We have pushed people to really make those four days of the week super productive.

I'll give you a sports analogy. In interval training, you do an interval really hard, then rest. Where it breaks down is if you don't do the work hard and you don't take advantage of the rest. 

The four-day calendar is rigorous. It can't be three-and-a-half days. Things can't get slow Thursday afternoon, you have to work all the way through. 

How do you measure success? How can you tell this works?

We don't get it right all the time. On average, people are working really hard those four days. They work more if they have deadlines. Because it's not officially a workday, people treat Friday as a looser opportunity to get things done or cross things off of their to-do lists. It helps people feel they have the freedom to get things done.

As far as productivity, I'm not seeing anything like this product has not shipped on time or we're not delivering this quarter because we are only working four days.

Still, it's a privilege for employees, right?

It goes without saying that the four-day workweek is a privilege, and we have to show up every day and earn that privilege. The minute we stop delivering the outcomes our shareholders expect, we are not going to have a four-day workweek.

Is four days of work and three days of rest the ideal work-life balance?

You're balancing the amount of effort that's required with the amount of recovery required for people to feel like they can work really hard.

Often we underappreciate how much the quality of the work is the most important thing, and when we are rested and are the best versions of ourselves, the quality shines.

How are ThredUp's employees responding to the change?

Before the experiment, we heard consistently from folks how much they value a three-day weekend. They came back feeling recharged. So I think the psychology there is about feeling recharged coming back into work. I wanted to create that level of freshness that leads to better outcomes. 

Some people do work Fridays. There's something about waking up Friday morning with a fresh cup of coffee with no emails, no Slack messages and banging out a creative proposal or performance review or product design. There's a freedom you have when you don't have all these inbounds coming at you. 

How do you define "better outcomes"?

It's hard to prove that the work quality is better. But we have a set of things we're trying to accomplish as a public company. We have standards and we know how long it's supposed to take to get things done. We're not allowing people to work one day less to push things out. 

What I most worry about is when things start to drag. When something that could get resolved Thursday afternoon doesn't and you have to wait until Monday. But if you have the right mindset, and the right employees, you get it all done. 

Do you think every company should shift to a four-day workweek? Why might it not work for everyone?

I don't know if it's something I would advocate globally for every company. It works for us because of the mission-driven nature of what we do. 

Our people are inspired to come to work and care about the impact we're making on the world. So they're willing to be flexible and work super hard on those four days in service of that mission. 

I could see an environment for folks who don't like their jobs or the companies they're working at, how this could go horribly wrong.

How many days a week do you work?

Because I am the founder, I basically work all the time. As founder you never shut your love of the company off. I never complain about working hard. I am the luckiest guy around.