When Palo Alto launched its business registry last year, the goal was to gather data about employees' parking and commuting habits -- information that would help city officials design new transportation programs and land-use policies.

Last week, as the city released employee information from the registry, one conclusion quickly emerged: The data isn't very reliable.

According to a report from the office of City Manager James Keene, staff believes about 93 percent of businesses (2,606 out of 2,797) have complied with the registration requirement. The number does not include those businesses that are not required to register -- namely, home-based businesses and "transitory businesses" with corporate offices outside the city. This includes 954 downtown businesses representing 15,641 employees.

But while the rate of participation is deemed high, some of the numbers in the registry don't add up. Several companies had elected to register twice while others didn't register at all. In some cases, companies greatly overstated their "total square footage" or misstated their parking spaces. In a report released last week, city staff note that the data is based on "self-reported figures that have been through only a basic level of staff analysis/quality control."

"Although some errors related to multiple registrations were removed, additional errors are likely to be included in the data set," the report notes. "However, with 93 percent of businesses registered (and likely a larger percentage of the overall employment), the data is representative of the businesses in Palo Alto required to register."

For local watchdogs, the errors in the registry were easy to spot. Consider the case of 550 Hamilton Ave., a downtown building that according to the registry houses more than two dozen businesses (most of them medical offices and professional services).

In most cases, the companies at 550 Hamilton Ave. report their "total square footage" to be between a few hundred square feet and about 1,500 square feet. But, as resident Jeff Levinsky discovered while poring over the data, there are some anomalies. Quartzy, a lab-management company with 0-25 employees, claims a total square footage of 35,678 square feet, Levinsky observed. If this is accurate, this would come out to more than 1,000 square feet of space per employee -- a highly unlikely scenario.

Hamilton-Webster Building, LLC, which lists the same employee range as Quartzy, also reported total square footage of 35,678. Given that the entire building at Hamilton and Webster is 42,000 square feet in size, both companies cannot be right (as partial compensation for this overstatement, two medical practitioners in this building reported their respective total square footage as 0 and 1).

While anomalies are one problem, omissions are another. Levinsky noted in a statement to the City Council this week that Safeway is missing from the registry, despite the fact that it's one of the city's largest grocery stores and one of Midtown's most prominent employers. Also missing is Caffe Riace, a restaurant near the California Avenue area that is best known among land-use watchdogs for its expansive patio (which was originally constructed as a "public benefit" for a nearby residential development but subsequently taken over by the restaurant), Levinsky noted. You also won't find McDonald's in the registry, even though its famous double arches are displayed prominently on El Camino Real.

Other businesses appear to have gone beyond the call of duty and registered more than once. The registry shows two entries for the marketing firm ShareThis, located on Miranda Avenue. Levinsky also observed that The Epiphany Hotel registered twice (once under the name of its management company).

Levinsky also observed that in some cases, the square footage appears to be greatly exaggerated. Volvo Palo Alto, for instance, lists as its square footage an eye-popping 259,000 square feet, which Levinsky noted is five times the size of the dealership lot. The problems in the registry data, Levinsky said, are obvious.

"It's not a reliable basis for any policy making," Levinsky said.

While the staff report suggests that the data, while imperfect, is "representative" of the business community, the discrepancies make it difficult to draw firm conclusions. Among the big questions that the registry is supposed to help answer is: How much space does a typical employee take up? Currently, the city's parking requirements assume about 250 square feet per employee. Some residents have long maintained that employee density is much higher at downtown startups, which often eschew traditional offices and cubicles in favor of open-plan layouts and tables crowded with software engineers.

The business registry suggests that downtown offices have an employee density of 394 square feet per worker, which belies the common notion that today's workspaces are more crowded. But a closer look at the numbers makes this conclusion seem less than ironclad.

For many of downtown's startups and mid-sized companies, the data can be too broad to enable specific conclusions. RelateIQ, a subsidiary of Salesforce, is located at 502 Emerson St., a block between University and Hamilton avenues that is the home to an eclectic group of retailers, restaurants and startups. The registry shows RelateIQ's total square footage at 46,545 square feet and its employee count at between 101 and 500.

This means that its space per employee is somewhere between 93 square feet and 465 square feet -- a range that does little to clear up the ongoing debate over employee density. Furthermore, while staff analysis notes that employee densities vary widely from one company to another, the report also notes that about 88 companies had less than 100 square feet per employee.

Neilson Buchanan, a Downtown North resident who has been heavily involved in the establishment of downtown's parking-permit program, also studied the registry data and noticed its many flaws. In addressing the council Monday, Buchanan emphasized the critical importance of gathering good data and urged the council to add staff resources to collecting and reviewing the data.

To date, he said, city staff has been "fighting with one hand tied behind their backs with the lack of resources." He urged the council and its Finance Committee to pay careful attention to address the resource shortage.

"I pored over the integrity of data," Buchanan said. "You don't want to dig too deeply into it."

Thomas Fehrenbach, the city's economic development manager, told the Weekly that the data is is still in its "preliminary, raw state." As the city adds resources and expertise in data quality, the registry "will tell a more accurate picture." Given the great interest in the data, he said, the city wanted to release it to the public even though there has been very little applied to it in terms of quality control.

"It's a valuable set of data about the business community, but as you break it down to granularity, its usefulness is not quite where we'd ultimately want it to be to draw conclusions," Fehrenbach said.