\begin{table}[htbp]\centering
\def\sym#1{\ifmmode^{#1}\else\(^{#1}\)\fi}
\caption{Within-Legislator Results (By Year), 2009-2016}
\begin{tabular}{l*{4}{c}}
\hline\hline
                    &\multicolumn{1}{c}{(1)}&\multicolumn{1}{c}{(2)}&\multicolumn{1}{c}{(3)}&\multicolumn{1}{c}{(4)}\\
                    &\multicolumn{1}{c}{Real Spending}&\multicolumn{1}{c}{Real Spending}&\multicolumn{1}{c}{Real Spending}&\multicolumn{1}{c}{Real Spending}\\
\hline
Electoral Security (MRP)&     -8754.3\sym{*}  &     -9475.4\sym{*}  &                     &                     \\
                    &    (4251.9)         &    (4319.9)         &                     &                     \\
[1em]
Electoral Security (Cook)&                     &                     &    -19285.5\sym{**} &    -19056.7\sym{**} \\
                    &                     &                     &    (6149.3)         &    (6058.7)         \\
[1em]
DW-Nominate (First Dim.)&                     &    139478.6\sym{*}  &    126955.3\sym{*}  &                     \\
                    &                     &   (61690.2)         &   (62488.1)         &                     \\
[1em]
Retiring            &                     &    -11371.2\sym{+}  &    -12815.3\sym{*}  &                     \\
                    &                     &    (6475.8)         &    (6381.4)         &                     \\
[1em]
House Tenure        &                     &      8873.2         &      7814.4         &                     \\
                    &                     &    (8304.3)         &    (7664.8)         &                     \\
[1em]
Majority            &                     &       274.7         &      -639.3         &                     \\
                    &                     &    (2885.8)         &    (2840.8)         &                     \\
\hline
\(R^{2}\)           &       0.386         &       0.392         &       0.395         &       0.390         \\
Observations        &\num[group-separator={,}]{3509}         &\num[group-separator={,}]{3507}         &\num[group-separator={,}]{3507}         &\num[group-separator={,}]{3509}         \\
Number of House Members&\num[group-separator={,}]{693}         &\num[group-separator={,}]{693}         &\num[group-separator={,}]{693}         &\num[group-separator={,}]{693}         \\
Member Fixed Effects&         Yes         &         Yes         &         Yes         &         Yes         \\
Year Fixed Effects  &         Yes         &         Yes         &         Yes         &         Yes         \\
\hline\hline
\multicolumn{5}{l}{\footnotesize Heteroskedasticity robust standard errors clustered at the member level in parentheses}\\
\multicolumn{5}{l}{\footnotesize \sym{+} \(p<0.1\), \sym{*} \(p<0.05\), \sym{**} \(p<0.01\), \sym{***} \(p<0.001\)}\\
\end{tabular}
\end{table}
