Are they blue?

One of the major themes of election reporting in this campaign has involved "blue-collar" or "working class" support for Donald Trump.  But few surveys ask people about their occupations today, so usually journalists treat class as equivalent to education.  For example, a Los Angeles Times story entitled "How do Americans view poverty? Many blue-collar whites, key to Trump, criticize poor people as lazy and content to stay on welfare," said the racial difference in opinions about who had the greatest responsibility for helping the poor "lay almost entirely with blue-collar whites--those without college degrees."  Of course, education is associated with occupation, but how strong is the association?  The Current Population Survey contains information on both education and occupation.  Civilian occupations are classified into 22 groups:  

Management

Business and Financial Operations

Computer and mathematical science

Architecture and engineering

Life, physical, and social science

Community and social service

Legal

Education, training, and library

Arts, design, entertainment, sports, and media

Healthcare practitioner and technical

Healthcare support

Protective service

Food preparation

Building and grounds cleaning and maintenance

Personal care and service

Sales

Office and administrative support

Farming, fishing, and forestry

Construction and extraction

Installation, maintenance, and repair

Production

Transportation and material moving

I divided them into four groups, with divisions indicated by the blank lines.  The last group of occupations corresponds with what people normally call "blue-collar"--they involve making or extracting some tangible product.   The first and third groups would clearly be "white collar" jobs--the difference is that the first generally involves more skill and higher pay than the third.  The second group is hard to classify by the blue collar/white collar distinction--like most white-collar jobs, they produce services rather than goods, but in terms of skills and autonomy, they are closer to blue-collar jobs.  

The occupational distribution of people with different amounts of education (rearranging the order to put the two white collar groups together):

                         White Collar

                Manager/Prof  Other   Service  Blue-Collar               

Not HS graduate         7%    17%        34%       41%

HS only                19%    25%        22%       34%

Some College           29%    31%        21%       19%

College Grad           64%    22%         8%        7%

Master's               84%    10%         3%        3%

Professional/Doctoral  92%     4%         2%        1%

Few blue-collar workers have college degrees, but a lot of people without college degrees are NOT blue-collar workers.   Considering everyone without a college degree, only 29% are blue-collar workers in the narrow or traditional definition.  Another 23% are service workers, so on a broader definition you could say a little over half are blue-collar workers.  

The reason that lacking a college degree is not synonymous with having a blue-collar job is partly that there just aren't that many blue-collar jobs in the United States any more, and partly that even people with only a high school diploma have a decent chance of obtaining a white-collar job (which might involve supervising blue-collar workers).  

Looking at it from one direction, it's strange that given the contemporary interest in class, few surveys bother to ask people what kind of work they do.  Looking at it from another direction it's strange that when given a straightforward measure of education, people call it "class" rather than "education."