The secret of success

 In 1939, the Gallup poll asked "Do you think people who are successful get ahead largely because of their luck or largely because of their ability?"  They asked the question again in 1970, and CBS news asked it in March and September 2016.  

                Luck         Ability        DK/NA
1939         16%            80%           4%
1970           8%            86%           6%
3/2016       14%            81%          6%
9/2016       11%            80%           6%

At each time, overwhelming majorities said that ability was the major cause.  That's important in itself, but differences by social standing are also of interest.  The 1939 survey contained an interviewer rating of economic standing, and people who ranked higher were more likely to say that ability was what mattered.  The 1970 and 2016 surveys didn't have the interviewer rating, so that can't be used for comparison, but both the 1939 and 1970 surveys asked about occupation, so you can compare occupational differences:

The figure shows the log of the odds ratio of ability to luck answers by occupational group.  I classified the occupations as higher to lower:  business and professionals, then farmers and white collar workers, then skilled manual workers, with semi- and unskilled manual workers at the bottom.  At both times, people in "higher" occupations were more likely to say ability, but the relationship seems weaker in 1970--the estimated slope is about 1/2 to 2/3 as large, and there is more scatter around the line.  

The 2016 survey didn't ask about occupation, but it did ask about income, which can be used to compare it to 1970.  Of course, the income categories were different, but there happened to be 11 each time, so to keep things simple I'll just number them as 1 through 11.

There was a clear relationship in 1970--people with higher incomes are more likely to say that success depends on ability--but not in 2016.  

Over the whole period, the relationship between social standing and opinions about the cause of success has become weaker, and maybe even disappeared.  Rather than looking down on the working classes, as critiques of "meritocracy" claim, people in the upper and middle classes have become less likely to assert their superiority.  I've argued this before, but didn't have such direct evidence.  

[Data from the Roper Center for Public Opinion Research--with special thanks for obtaining the 2016 survey]