A few days ago, my wife sent my daughter to the corner on an errand run. We had a few guests, and everyone was in need of coffee, and my daughter needed something to do. My wife carefully wrote out a list of drinks and snacks — including a piece of chocolate-chip banana bread and a hot chocolate as payment in kind for the errand girl — and sent her on her way.

 

This was basically her first big shot at running an errand like this all by herself. She was ecstatic at the opportunity.

 

We live within walking distance of the high-rise financial district of a city of a million people with one of the lowest crime rates in North America for a city its size. The coffee shop is half a block down our residential street, at the corner where it intersects a busy, trendy commercial street. There are no cross streets between here and there, but our daughter does have to pay careful attention at the alleyway that backs on the retail strip, because there’s fairly frequent traffic heading to and from back-lane parking lots and garages. We’ve been sternly warning her about looking both ways at the alleys for years, so we have no real worries there.

 

Once she’s past the alley, she walks by a busy, beloved neighborhood pub, where at certain times of day there are smokers or other mildly inebriated folks occupying the sidewalk. At the corner where the coffee shop is, there’s constant foot traffic, sometimes including local homeless folks peddling papers, canvassers for non-profits, even the odd crazy or drunk. On the wrong day, she might even have to traverse a dense herd of hipsters, who in our experience are uniquely oblivious to the presence and priorities of small children.

 

We deemed all this an acceptable level of risk, and the mission went off without a hitch. Not only did everyone get a coffee and our daughter earn a treat, but the sense of capability and responsibility she came home with is one of those invaluable life skills you can only teach by nudging the bird out of the nest and hoping the wings flap hard enough.

 

So here’s the key question: How old do you think our daughter is? How old do you think she’d need to be, if she were your girl?

 

The answer, anyway, is 6 years old. And I’d wager that that piece of data strikes you somewhere on the perfectly-normal-to-wildly-irresponsible scale based on the relative conditions of the neighborhood you live in. As parents, we gauge these things subjectively, highly unscientifically, based on everything from our neighborhood’s general vibe and friendliness to our own kid’s maturity and our own appetite for risk.

 

There are, however, some more objective ways of thinking about this, and while they probably won’t change any individual parents’ minds, they make interesting food for thought as many of us prepare to take our kids door to door across our respective neighborhoods to beg for sweets.

 

I got to thinking about all this because my hometown newspaper ran a Halloween-themed story rating the city’s neighborhoods on a “Trick or Treat Index.” The idea was inspired by the annual trick-or-treat rankings published by celebrity urbanist Richard Florida, and the paper’s index also included some of the thinking behind Catherine Austin Fitts’ “Popsicle Index.”

 

Very loosely speaking, Florida’s index aims for quantitative data at the scale of an entire urban area, while Fitts’ index is a qualitative measure that can be applied household by household. Florida counts demographics, population density, walkability (based on the percentage of non-car commuters), median income (assuming — speciously, I’d argue — that wealthier people give out more and better loot) and “creative spirit” (based on the percentage of people working in creative industries).

 

Fitts, by comparison, asks a single simple question: Would you feel safe letting your kid walk alone to the nearest store in the neighborhood to buy a popsicle? The higher the percentage of parents answering yes, the better the score on the Popsicle Index. Her base case is her childhood working-class neighborhood in West Philadelphia in the 1950s, where the Popsicle Index was 100 percent — where indeed it probably would’ve seemed absurd, even cruel, not to let a kid go down to the corner store and buy a popsicle.

 

In the final analysis, I’m a Fittsian, because I believe it better expresses gut truths about social cohesion and parental trust and the actual street-level reality of the neighborhood than Florida’s reams of data can. Florida can tell you what a place might be like, how theoretically safe and rewarding it might be to go trick-or-treating in a given city; Fitts will tell you whether parents actually let their kids roam free in those places, whether the actual functionality of the city’s neighborhoods permits what has rather sadly become the “alternative” lifestyle of free-range parenting.

 

My local paper leans more toward Florida’s approach, and since I can speak to the specifics of its results best, I’ll use it as my case in point. My neighborhood, which has very nearly the highest WalkScore in the entire city (which is pretty much the No. 1 reason we bought a house here) didn’t even crack the top 10 on my local paper’s Trick or Treat Index. We have higher-than-average property values in my ‘hood, but we also have lots of rental units, smallish lots and a good number of old, teeny bungalows; the top five neighborhoods on my hometown Trick or Treat Index are all very affluent neighborhoods (the top three all have average property values on the fabulously well-to-do side of a million bucks).

 

Even more surprising, though, is that we got beat by a couple of outer-ring suburban enclaves. My best guess is that because property values and percentage of population under the age of 15 had equal weight with WalkScore and density and such, our local Trick or Treat Index skewed toward brand-new suburban neighborhoods filled with young families who’d used the tried-and-true “Drive Until You Qualify” approach to homebuying. One of these neighborhoods, for example, has a single-digit WalkScore, which if I understand correctly means you live in one of those neighborhoods where, in ordinary day-to-day circumstances, letting your kid walk anywhere qualifies as criminal negligence.

 

So yeah, sure, any given suburb might have enough young families in it that kids go trick-or-treating in droves despite their circumstances, each one hovered over by a parent or two as they traverse the broad lots and sidewalk-less avenues to collect some candy. But what does that say, really, about the other 364 days of the year? Would it even be physically possible — let alone safe — for a 6-year-old in such a neighborhood to pick up a popsicle (or a hot chocolate) from the local shop?

 

Or think of it this way: What if there were one more column of data on my local paper’s index, a Fittsian one that polled local parents to ask how old their kids would have to be before they could go out trick-or-treating alone. I know we’d answer 8 — maybe even 7 — around here. (Not quite yet, in other words, but soon.) And I think that probably says more about the real walkability — the real sustainability — of a neighborhood than property values or demographic stats do.

 

Or as a parent, you could simply ask yourself this: When your kid went trick-or-treating, was it the only day this year she navigated the neighborhood on foot to conduct an errand?

 

To talk the walk(ability) 140 characters at a time, follow me on Twitter: @theturner. My new book, "The Leap: How to Survive and Thrive in the Sustainable Economy," is available now from Random House Canada.