(Bloomberg) -- Am I on track for retirement?

It’s a simple question. But to answer it accuratelyand make sure you don’t outlive your money, you need powerfuldata and high-level math. And, even then, a leap of faith.

Online retirement calculators usually make just enoughassumptions to be dangerous. What if you live 10 years longer thanyou planned for? What if the market tanks? What if you needastronomically expensive round-the-clock health care?

The answer you typically get from financial advisers is tosave as much as possible, or way more than you could ever spend,and hope for the best. The result is workers scared toretire and retirees terrified to spend a dime on anything funor frivolous.

Now comes United Income, a new money manager backed bysome of the biggest names in retirement, pitching big data as asolution. It’s deploying huge sets of stats on investmentperformance, retiree spending, longevity, and other crucial factorsto simulate innumerable outcomes.

The software estimates the chances that eachclient’s personalized retirement strategy will actuallysucceed, then refines the plan if it won’t, based on as manyas 18 million simulations per client, UI said. The aim isto make retirees’ money go a lot further than otherplanning software, which Founder and CEO Matt Fellowes scorns ashopelessly out of date.

“We’ve invented a new approach to moneymanagement,” Fellowes said in aninterview.

That may sound familiar, but Fellowes, 42, has some street cred.A member of the family that owns Fellowes Brands, a 100-year-oldconglomerate, he’s a former Brookings Institution scholar.In 2009, he started HelloWallet, which companies hire togive financial help to employees.

Morningstar Inc. acquired it in 2014 for $52.5million, and Fellowes became the investment research giant’schief innovation officer. Now, Morningstar is helping to backUnited Income, with more than a third of the $5.8 million raised sofar. The new firm officially opens to investorstoday.

“It’s a bet on Matt, and that he can build an exceptional teamto tackle a really difficult investor problem,” said Joe Mansueto,Morningstar’s founder and chairman. “It’s a business opportunity,but it’s also a way to improve the retirement of millions ofAmericans.”

Basic retirement calculators just do math, estimating how moneymight grow over time. The more sophisticated calculators usehistorical market data to game out the best- and worst-casescenarios for investment performance.

United Income does that, too, butFellowes stresses the many “future life outcomes” itmodels. By focusing on investing, he argues, otherfirms ignore the two most important questions in retirement:When are you going to die, and how much are you going to spendbefore you do?

To get the answers, United Income, whose 18 full-time employeesare based in Washington, D.C., got advice from prominent people inpolicy and investing circles. J. Mark Iwry, a keyarchitect of retirement policy in the Obama administration, islisted as an adviser, along with Stephen Utkus, directorof Vanguard Group’s Center for Investor Research; John Wider,a former president and CEO of AARP Services, a wing of theretiree organization; and several other former governmentofficials.

Health, exercise, and, increasingly, education and socioeconomicstatus can help predict how long we live. Even as the averageAmerican’s longevity has stalled, there are affluent,well-educated fitness freaks who should probably plan onhitting 100. United Income asks clients about these factorsand then uses detailed actuarial tables to estimate longevity.It does the same for spending, tapping government data to plotout how people might actually consume over the course oftheir retirements.

“Everybody’s spending curve is different,” Fellowes said.Spending on essentials tends to stay the same throughoutretirement and may even decline—for example, if retirees payoff their mortgages. But discretionary spending, such astourism, tends to spike at the beginning of retirement. Health carespending, though essential, is usually concentrated at theend. Your spending pattern is further affected byyour marital status, financial situation, health, and otherfactors.

United Income crunches all these data and makes recommendations.It gives advice on the best times to take Social Securitypayouts and make taxable retirement account withdrawals, and buildsand manages custom investment portfolios using low-costexchange-traded funds. The key to making nest eggs go further,Fellowes said, is an automated, sophisticated investingstrategy based on each client’s estimated requirements.

For example, your essentials, such as utilities,groceries, and mortgage payments, must be covered with ultra-safesources of income such as Social Security, pension payments,annuities, or conservative, bond-heavy investments. That letsyou take more risk, and in theory get higher returns,with money you’ve set aside for other goals, which clients cancustomize. Money for an around-the-world trip might go in anaggressively risky, equity-heavy portfolio. The strategy fora granddaughter’s college fund will depend on how soon thegirl graduates from high school. Money for major healthcare expenses, which often occur later in retirement, canstart out in risky investments and move to safer ones overtime.

It might not sound like rocket science, but many advisersstill base their strategies on basic rules ofthumb, guessing at a client’s longevity or relying onaverages to estimate spending needs. A common method is to predictspending based on a percentage of pre-retirement income,like 80 percent.

“All those rules of thumb made sense in a world that could notpersonalize data,” Fellowes said. “They just don’t make senseanymore.”

As a result, he said, retirees are often told to invest tooconservatively. A 70-year-old with a modest lifestyle mighthave almost all her essentials covered by Social Security or aguaranteed pension. That gives her lots of freedom to investaggressively, to build up a fund for late-in-life health care, andeven to splurge on the occasional luxury.

United Income’s approach could be a big step forward inretirement planning—if its models work.

“The challenge is execution,” Mansueto said. Fellowes has“got great ideas, but there’s a reason that it hasn’t been solvedyet.”

United Income will have to get every detail right. Its maintarget is people between 55 and 70 with $300,000 to $3 million toinvest. A plan that succeeds for these clients nine timesout of 10 will still fail an unacceptable number ofpeople.

“When you’re giving investment advice, the guiding principle is‘do no harm,’” said Anthony Webb, research director atthe Schwartz Center for Economic Policy Analysis at the NewSchool for Social Research. Webb hasn’t reviewed UnitedIncome’s methodology but warns of the difficultyof creating customized retirement plans that work foreveryone. You can try to estimate a client’s longevity, forinstance, but even with major health problems he or shestill has a small chance of living to a very old age. You haveto hedge that risk, he said.

One way is to recommend insurance products. United Incomedoesn’t but is exploring adding simple annuities anddeferred annuities, also known as longevity insurance, to itsplatform.

Clients can monitor their plan’s risk of failing inreal time. When they log on, they’re greeted by a meter gauging“our confidence that this plan will succeed” and told how manyof their spending goals are still on track. Don’t expect thatconfidence number to waver much, though, Fellowes said, even if thestock market plunges 20 percent in one day. The calculationsare based on all the factors that go into UI’s models,spread out over the rest of a client’s life.

United Income charges an annual fee of 0.5 to 0.8percent of assets, depending on the level of service clientswant and how much money they invest. (UI also offers a financialplan and Social Security advice for free.) It also keeps trackof cash and investments held with other institutions and takesthose assets into account when making recommendations. Aheadof its official launch, UnitedIncome said it has collected more than $200 millionin assets since late July.

Why haven’t more financial firms amped up the data piece oftheir retirement-planning tools this much? It’s hard. Foryounger workers preparing for retirement, everyone’s goal is prettymuch the same, to save and invest as much as they can. Butafter age 55, the standard advice doesn’t work aswell and subjective measures matter more. How much do youlike your job, and how secure is it? Where do you want to live?How’s your health?

Another reason many retirees don’t get sophisticated advice:Lots of firms try hard to sell clients a mutual fund oran annuity to reap a commission, but after the sale iscomplete they’re much less interested intheir day-to-day money management needs.

That gives United Income an opportunity, if clients findits advice valuable. And that could put even morepressure on the nation’s incumbent financialadvisers, already facing rapid change andincreasingly demanding clients who have goodreason to be skeptical of their advice.

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