Robots or people?

By Gerard Cachon and Christian Terwiesch, The Wharton School at the University of Pennsylvania. Source: Matching Supply with Demand.

Christian Terwiesch

Gérard Cachon

Maybe the biggest challenge for e-commerce retailers is dealing with the huge surge in sales in the fourth quarter.  How can you build enough capacity cheaply enough to satisfy the rapid growth in demand during October, November and December, only to have most of that demand disappear by January? The traditional approach is to hire lots of seasonal workers. The trick with this is to be able to train them quickly enough for them to be productive in time for when they are actually needed. The Wall Street Journal reports that one company, Kiva Systems, has a different idea – instead of hiring workers, install robots (Dec 19, 2010).  To see these robots in action, check out the video (click here).

You might assume that these robots would “walk” around a warehouse picking products, putting them into a basket and bringing them to a place to be packaged. That is what humans do. Instead, these robots move shelves of inventory around. (See the photo – the robot is the orange contraption at the bottom of the shelf.) One advantage of this system is that you don’t need permanent aisles between the inventory – the shelves can be packed in tightly with the computer controlling the sequence (so that the one pink doll you need isn’t buried deep within a sea of shelves).

The next thing you may notice is that these robots are not particularly fast. It is not like the robots move product through the warehouse at twice the speed a human can walk. However, assuming these things are reliable (e.g., treads don’t need replacing every couple of days) they don’t need to take breaks, and they are instantly trained. One downside of this system is that the robot must move the entire shelf and not everything on the shelf may be needed at one time. Humans pushing a cart around a warehouse only put into their cart what is needed at the time.

But the point of the article is how to deal with the holiday surge in demand. While a robot might replace a human, it doesn’t eliminate the problem – the company simply needs a lot more capacity in the 4th quarter. If it buys these robots, then they are likely to be idle most of the rest of the year. Seasonal employees are just that – seasonal – that is, they go into the deal with the expectation that their work will be temporary.

The article ends with an idea for making the robots more cost effective for the retailer – Kiva Systems will rent the robots to the company for just the peak demand period. But I don’t see why this solves the problem – now Kiva Systems is sitting on expensive and idle capacity for most of the year (even in the Southern Hemisphere, Christmas falls in December).  Rental systems work well when potential customers need the product at different times. Given that the 4th quarter is the same for all retailers, I am not seeing this as an idea that works. Interestingly, the founders of Kiva Systems worked previously at Webvan. If there was ever a company that invested too much in replacing human workers with technology, it was Webvan – they may have survived if they didn’t blow all of their capital on hugely expensive warehouses. That said, I suspect there are surely applications of the Kiva Systems for some retailers. But as a solution to the 4th quarter demand surge, I am skeptical.

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One Response to Robots or people?

  1. Roger Bohn says:

    Absolutely! Replacing people with fixed capital is precisely the WRONG direction to go for dealing with fluctuating demand. Capital equipment is less flexible (in terms of activity) and more expensive to carry on the books.

    That said, we can speculate on how we would do this ourselves. A key issue is the average or fully utilized cost of the robots versus manual alternatives. (Also, what they are replacing is another capital-intensive approach, the ASRS, which is probably even less flexible.) If these robots are cost-effective at say 70% utilization, then we can imagine a business model which rents them out to a business where it’s easier to hire and train seasonal labor. The renter then hires the temporary employees, instead of the main owner. During the peak season, the other firm takes them back.
    It’s hard to figure out how the numbers would work, but it’s conceivable. Maybe the robots could move downstream in the supply chain in September -October-November-December, following the “bubble” of goods? By December, they are in the back room at Sears/Walmart! In February, they get shipped to China?!

    Still, considering the founders’ Webvan history makes one skeptical, as you say!

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