Commuting to Silicon Valley

What is Silicon Valley? Where is Silicon Valley? Is there a Silicon River? Well, others have written about this extensively, so I’ll just point to the wikipedia article on Silicon Valley.

For the most part, I’m equating “Silicon Valley” with Santa Clara County, California. The Bureau of Labor Statistics also publishes current data on employment patterns in “Silicon Valley” as the “San Jose-Sunnyvale-Santa Clara Metropolitan Statistical Area (MSA).” But be very careful, as this “San Jose-Sunnyvale-Santa Clara MSA” area includes Santa Clara County AND San Benito County (Hollister, San Juan Bautista, Pinnacles National Park.)

The American Community Survey data included in American FactFinder is quite valuable in depicting year-to-year changes in big picture commuting data:

  • Resident Workers by County-of-Residence (Table B08007);
  • Workers living-and-working in the County-of-Residence (Table B08007);
  • Workers-at-work by County-of-Work (Table B08501).

The term “workers-at-work by county-of-work” seems a bit cumbersome. Why not just use the term “jobs”? Well, “jobs” (or “total employment”) is a count of the number of employed by area-of-work. On the other hand, “workers working in county-of-work” is a “body count” of workers, not the job (or jobs) held by those workers. Workers may have one of more jobs (“moonlighting jobs”). So, “jobs” or “total employment” is always greater than “workers-at-work.” It’s usually about 3-4 percent higher, and reflects the moonlighting rate for workers with multiple jobs.

Here is a chart showing workers-at-work in Santa Clara County between 2006 and 2015:

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Where’s Waldon? Places in Contra Costa County (Part 2)

Today’s post examines the interesting places in Contra Costa County, California. Yesterday I posted about Waldon, which is now Contra Costa Centre. Waldon/CCC is a small unincorporated “island” between Walnut Creek and Pleasant Hill, just around the Pleasant Hill BART station.


Mountain View is not just a City in Santa Clara County, but also an unincorporated “census designated place” (CDP) in Contra Costa County. (This was a big headache for me in my former career, when the Census Bureau showed a massive increase in commuters from Contra Costa County to Santa Clara County. I questioned the Bureau folks about this, and they found out that they had mis-coded Mountain View CDP to Mountain View City. Thankfully they corrected the data! This was in the early 2000s, and was before Google boomed to be one of the largest employers in Silicon Valley. I thought it was due to the Kaiser Hospital in Martinez being in the Mountain View CDP, but I’m not sure about this.)

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Where’s Waldon: And Other Stories of East Bay Places

One of the more interesting aspects of census data are changing place names over the decades. This post is a little more lighthearted, less serious, and highlights some of the fun/historical/cool data from the census.

The focus of this post are places in Alameda and Contra Costa Counties in the San Francisco Bay Area, California.

Where’s Waldon?

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Waldon was a Census Designated Place (CDP), an unincorporated area in the middle of Contra Costa County, California. It only existed for the 2000 Census, and had a April 1, 2000 population of 5,133. Where the name “Waldon” came from, I have no idea (and neither does Wikipedia!) It was renamed for Census 2010 as “Contra Costa Centre” with a April 1, 2010 population of 5,364. It’s basically an “unincorporated island” around the Pleasant Hill BART station.

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Health Insurance in the USA (Part 3)

It’s been a long time since my last post. I was traveling the American Southeast, mostly as part of a Road Scholar Trip: “Heart of the Civil Rights Movement.” An amazing trip.

This post looks at the share of Americans who have no health insurance, in 2015, by US Congressional Districts. The lowest (best) congressional districts are in the State of Massachusetts. Eight Massachusetts districts rank in the top eight, ranging from a low of 1.9 percent uninsured (Massachusetts District #8, Lynch, D-Boston) to 3.2 percent uninsured (Massachusetts District #9, Keating, D-Bourne).

File:Massachusetts congressional districts large.pdf

In ninth place is the Minnesota 6th Congressional District (Emmer, R-Delano). And in tenth place is the Illinois 18th Congressional District (LaHood, R-Dunlap).

This is all based on data from the 2015 American Community Survey, Table GCT-2701.

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Warm and Fuzzy vs the Cold Hard Facts

The ongoing survey program by the US Census Bureau, the American Community Survey (ACS), provides a great opportunity to examine detailed and current trends in the USA. The American Community Survey has been said to contain “warm” (more current), and “fuzzy” (less precise) data, compared to the April 1st of each decade’s Decennial Census. (The Cold, Hard Facts!)

You won’t see mention of “standard errors” and “margin of error” in the Decennial Census data. It’s a 100 percent “sample” (that is, a “census”) without standard errors. (There are other errors associated with Decennial Census data, but that’s another story.)

I didn’t invent the metaphor of the ACS as a “warm and fuzzy” database. I think I first came across this in an article:

  • Heather MacDonald. “The American Community Survey: Warmer (More Current), but Fuzzier (Less Precise) than the Decennial Census” In Journal of the American Planning Association, Vol. 72, No. 4, Autumn 2006, pp. 491-503.

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Health Insurance in the USA (Part 2)

The share of the national population without health insurance, in 2015, was 9.4 percent. This is from the American Community Survey (ACS) conducted by the US Census Bureau. This is down from 15.1 percent uninsured in 2009. This is significant progress.

The 2015 uninsured share ranges from a low of 2.8 percent in Massachusetts to a high of 17.1 percent in Texas.

Massachusetts has the lowest uninsured rate (and highest insured rate) due to the passage of their state health care reform act in 2006, four years before the federal Affordable Care Act. Massachusetts has a four year head start on the rest of the USA.

Texas (17.% uninsured) has not expanded their state Medicaid program after passage of the federal ACA. Alaska (14.9% uninsured) at the second highest, has expanded the state Medicaid program. Rounding out the top (or bottom) five states are: Oklahoma (13.9% uninsured), Georgia (13.9%) and Florida (13.3%). Only Alaska of these five states has expanded their Medicaid program.

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The Most Densely Populated Place in the USA is…..Friendship Heights, Maryland

The most densely populated place in the United States, as of April 1, 2010, is Friendship Heights Village (a Census Designated Place, or CDP), in Maryland. Friendship Heights is a small, 38 acre neighborhood on the border of the District of Columbia. Population = 4,698; Area = 0.059 square miles; Density = 79,627 persons per square mile (ppsm).

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