The first step for a shopper buying a suit at the fast-growing menswear retailer Indochino is sharing his personal information: A salesperson armed with an iPad measures nearly everything on his body, from the distance between his belly button and rear to the circumference of his knees.
The next step is getting a customized, made-to-measure suit delivered to his home within a few weeks. But his body data lives on: Company executives are hoping to build a "master data model" that would connect his measurements with his advertising, shopping and spending histories.
Clothing companies now see body measurements as one of their most prized currencies, and millions of Americans are increasingly offering up their innermost personal data in search of customized pieces or a better fit.
Companies such as Indochino, Wantable and Stitch Fix, the latter of which counted nearly $1 billion in sales last year, gather dozens of data points on each customer, including weight, jobs and past pregnancies. They are being joined by Amazon.com, the online-retail giant that counts fashion among its fastest-growing businesses and now sells a bedroom camera that offers opinions on what a user wears.
But the corporate harvest of data about our bodies, including our faces, voices and fingerprints, also is raising privacy concerns about how much sharing is too much in service of better-fitting clothes.
"These body measurements look a lot like medical records," said Peter Swire, a law professor at the Georgia Tech Scheller College of Business who coordinated with the White House in the 1990s during the shaping of the nation's medical privacy law.
Those health privacy rules, Swire said, "would apply to this data if the measurements were taken at the hospital. It doesn't apply when an online company puts them in an app."
Companies value this data because it can lock customers in for life and make it easy to order customized clothes over the Internet without trying anything on. But some privacy experts question whether Americans have a clear idea of what they are handing over.
"There's a little bit of a weirdness about it. You're letting people into your life," said Autumn Rocha, a 26-year-old student in Baltimore and Stitch Fix client. "But there's also something cool about it: 'This is what I'm into. What can you find for me?' "
A new Stitch Fix customer fills out a profile that compiles up to 85 data points. A woman is asked if she is a mother or currently pregnant, as well as her due date. She also hands over her dress, waist and bra size; her age, job and location; parts of the body she would like to flaunt or downplay; and answers to more-abstract questions, such as whether she likes taking risks.
Algorithms use that data to pick through Stitch Fix's inventory, referring options to a human "stylist" who decides on which to send. The customer pays to keep the clothes she likes and can send back anything she doesn't. She can't, however, go on the site and pick things out; her only choice is what the algorithms recommend.
The company says it can better assess style by having access to customers' Pinterest and Instagram accounts, which many customers willingly share. Company executives said others go a step further, sharing details of life milestones — new jobs, recent divorces, upcoming vacations and funerals — to define the clothes they are looking for.
Stitch Fix chief algorithms officer Eric Colson said he was surprised at how quickly customers were willing to share so much about themselves. At Netflix, where he previously led data science and engineering, the streaming-video service pushed to keep new users interested by removing as many questions at sign-up as possible. But at Stitch Fix, where building a profile can involve answering more than 80 personal questions, the follow-through rate is one of the highest Colson said he has ever seen.
"People love to fill out that questionnaire," he said.
Stitch Fix refers to its data-gathering in the terms of a lifelong relationship: Customers go on a "client journey," and the company pledges to be a "partner for life." In a presentation to investors in November, Stitch Fix outlined the spending history of a 36-year-old Indiana doctor whom, through switches to maternity wear, they could track through three pregnancies.
The company distinguishes itself to investors by saying it has rich, high-quality data provided directly by the client rather than taken from other sources. Customers are "motivated" to share as much personal detail as possible, the company said in financial filings late last year, "because they recognize that doing so will result in more personalized and successful experiences."
The technology has helped the company achieve incredible growth. Its more than 2 million active clients drove nearly $1 billion in sales last year, more than 10 times the company's revenue in 2014. The company has in a few years become one of the biggest online clothes sellers in the United States, with sales last year that rivaled department store giant J.C. Penney, according to data from market researcher Euromonitor.
Executives say this level of data has helped them gain ground in parts of middle America where fashion options are limited. Stitch Fix also says the data has helped it capture an underserved market of American women by offering styles and sizes they might not find in their local department store. When the company last year launched its plus-size offering, 75,000 women joined the waiting list.
The company now employs about 80 data scientists to help refine the algorithms that decide clothing deliveries, predict purchase behavior and direct clothes pickers along the fastest route through the company's five cavernous U.S. warehouses.
Traditional retailers are racing to catch up, acquiring or partnering with companies that can help them compete.
Nordstrom bought the clothing subscription service Trunk Club and partnered with Shoes of Prey, a customizable-shoe company. The Macy's subsidiary Bloomingdale's partnered with the personalized-bra company ThirdLove, which allows women to size their bust by taking selfies in the company's app.
Justin MacFarlane, the chief strategy, analytics and innovation officer at Macy's, told investors in June that the company is moving "very, very quickly" to build a robust data science team. "Five years ago, if you were to say there was a team of PhD data scientists at Macy's that are thinking about our most strategic problems, people would have thought you are crazy," he said.
But the new crop of data-oriented retailers has a clear lead over traditional brick-and-mortar giants. "For established companies to develop this level of technical expertise internally is going to take a very long time," said Bridget Weishaar, a senior equity analyst with Morningstar.
Many of the new retailers say they don't share or sell the size data they are collecting — it's too much of a competitive edge. Stitch Fix said it employs an internal security team and says it protects its customers by removing some identifiable information.
But privacy experts worry that the retailers eventually will be tempted to sell the data, which could prove incredibly valuable to marketers and health insurers. Or the information could become the target of hackers. Passwords can be changed; body sizes can't.
"The very first data breach of someone's jean size is going to be very treacherous for that company," said Pam Dixon, founder of the World Privacy Forum, a consumer research group. "This extraordinary profusion of health-related data is not covered under anything. You have to rely on the privacy policies of the company, and it's really not enough."
The companies say this mass gathering of data will inevitably bring about the next stage of how we all shop for clothes. Within five years, Stitch Fix's Colson said, we will look back and think it was preposterous that we wandered through malls, scavenging for clothes we liked: "Why was the onus on us as consumers to go figure out my size? What were we thinking?"
Retailers also are eager to find new ways to apply the data they have gathered en masse. Indochino's chief revenue officer, Peter Housley, said the company is gathering new measurements all the time and hopes to combine them soon with customer spending, past views of advertising and location data, including whether they had stopped or walked by one of their stores.
"We know a lot about our customer," Housley said. "We can now find you and serve up ads to you even if you've just got your device in your pocket."
The next step for gathering body size data may not be from a questionnaire. Amazon, which recently launched its own private-label clothing brands and introduced a try-before-you-buy clothing service called Prime Wardrobe, last year began selling a voice-activated camera, the Echo Look, that snaps pictures of what a user is wearing and offers what the company calls "a second opinion on which outfit looks best."
Molly Wade, an Amazon spokesperson, said this feature of the Echo Look, called Style Check, uses people's data to improve its algorithms.
She said the Echo Look does "not identify items in your photos that are not related to your outfit." When asked if there was interest in exploring that technology later, Wade said the company "wouldn't want to speculate beyond that."
Amazon founder and chief executive Jeffrey P. Bezos owns The Washington Post.
The company last year also bought the start-up Body Labs, which creates 3-D body models, and this month filed for a patent on a "blended reality" mirror that could reflect how someone would look in virtual clothes.
For now, many customers seem happy with what they get in exchange for what they share about themselves. Sarah Carlson, a 31-year-old stay-at-home mom living in a small suburb in Minnesota, signed up for Stitch Fix last fall after the birth of her daughter made shopping too much of a pain. She flinched at a couple of questions — "When it asked, 'What areas do you like to flaunt?' I was like, 'None of them' " — but now says she would not have half the clothes in her closet if she had not followed through.
She connected her social media accounts and spent some time filling out her Pinterest inspirations, to help the algorithm get to know her more.
"They know what fits me, my size, my style," she said. "What's the worst that can happen?"