R Conditional Regression with Multiple Conditions
Solution 1:
The problem is:
df$2010
If your data really has a column named 2010, then you need backticks around it:
df$`2010`
And in your subset, don't specify df twice:
subset(df, msa == 1, `2010` == 1)
In general it's better if column names don't start with digits. It's also best not to name data frames df, since that's a function name.