I recently had a conversation with Motorola’s Mark Wheeler—his colleagues call him the “warehouse guy,” an appellation of high honor in my opinion—and the topic of “wearables” came up. Wearables are light mobile computers with a ring scanner that are worn on the forearm. 

Mark told me there are cases where wearables provide better labor productivity than Voice Recognition systems. I expressed some politely-worded skepticism about this claim, so Mark pointed me to a 45-minute video webcast. I watched it and here are some of the highlights.

Robert Ulery, who at the time was the Director of Engineering at the third party logistics provider OHL, was one of the speakers. Robert and his team conducted a time study of wearables versus traditional handheld scanners at one of its distribution centers in Nashville. They found that in piece picking there was a 25 percent improvement in productivity over handhelds. In case picking, wearables provided 20 percent greater productivity. Previously, OHL had compared Voice to handhelds and it found that Voice provided a 10 percent productivity gain over handhelds. Therefore, for this particular warehouse and processes, wearables were between 10 and 15 percent more productive than Voice. 

Wearable’s greater productivity compared to Voice was attributed to two things. First, if a picker picked at a location and then his next pick location was very close by, order selectors sometimes had to wait for the voice command. Secondly, OHL’s warehouse had a fair amount of ambient noise. Pickers sometimes had to ask for commands to be repeated. 

The video shows two picking processes: order selection from cases on pallets on the floor and each picking from cases in racks.

I actually like the case picking application better despite the slightly lower productivity. Wearables are a hands-free technology, but they are not completely an eyes-free one. If an order selector was told to pick two cases from a particular location on the floor, he would go to the slot, scan it to prove he was in the right location, and then glance at the computer to verify pick quantity. Because selectors are always picking from the floor, and a pallet is fairly wide, I would think the chances of picking cases from an adjacent location would be virtually zero. 

In contrast, with each picking, when a selector glances down at the computer to see how many units to pick, I think there is a chance that when he looks back up, he might pick from a slot adjacent to the one he was supposed to pick from. Pick accuracy was not discussed in the video, but based on research I conducted a few years ago, I believe order selection mistakes are much more expensive than most logisticians realize. 

The one small drawback to wearables mentioned in the video was that it made some workers’ arms sweaty and itchy. Order selectors responded by wearing long sleeve shirts and OHL made sure that selectors got assigned dedicated wearables. Other than that, the cultural issues were minimal.

The other cool thing about this project is how cheaply OHL was able to run the pilot. Because the wearables and the handhelds are both provided by Motorola, and Motorola has a unified maintenance infrastructure, OHL was able to swap in the wearables with minimum IT expense. 

In conclusion, when it comes to RF handhelds, wearables, or Voice, the devil is in the details. You need to look very closely at the process. Small differences in the process can make big differences in which technology will actually provide the best ROI.