\begin{table}[htbp]\centering
\def\sym#1{\ifmmode^{#1}\else\(^{#1}\)\fi}
\caption{Cross-Sectional Results (By Quarter), 2009-2016 \label{TableCSByQMRP}}
\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)&     -3980.8\sym{***}&     -3054.3\sym{***}&                     &                     \\
                    &     (526.7)         &     (508.9)         &                     &                     \\
[1em]
Electoral Security (Cook)&                     &                     &     -4790.1\sym{***}&     -3824.9\sym{***}\\
                    &                     &                     &     (555.6)         &     (549.0)         \\
[1em]
Democrat            &                     &     -1362.4         &                     &     -2877.1         \\
                    &                     &    (3662.0)         &                     &    (3662.1)         \\
[1em]
DW-Nominate (First Dim.)&                     &      -326.5         &                     &     -1517.4         \\
                    &                     &    (3990.2)         &                     &    (3970.4)         \\
[1em]
Retiring            &                     &     -8445.5\sym{***}&                     &     -9650.7\sym{***}\\
                    &                     &    (1494.3)         &                     &    (1529.7)         \\
[1em]
House Tenure        &                     &     -1051.3\sym{***}&                     &      -978.1\sym{***}\\
                    &                     &     (137.8)         &                     &     (139.2)         \\
[1em]
Majority            &                     &      1599.7         &                     &       964.4         \\
                    &                     &     (998.5)         &                     &     (994.2)         \\
\hline
\(R^{2}\)           &       0.160         &       0.193         &       0.167         &       0.198         \\
Observations        &\num[group-separator={,}]{11329}         &\num[group-separator={,}]{11321}         &\num[group-separator={,}]{11329}         &\num[group-separator={,}]{11321}         \\
Number of House Members&\num[group-separator={,}]{693}         &\num[group-separator={,}]{693}         &\num[group-separator={,}]{693}         &\num[group-separator={,}]{693}         \\
Member Fixed Effects&          No         &          No         &          No         &          No         \\
Quarter 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}
