Line cut in \tabularx{}

• Log Damage X Log Adaptation is too long to fit into a single cell. The easiest fix is to manually move the second part of the phrase into the next line.

• If you are using a tabularx, you should use at least one X column to make sure the table can adapt to the available space

• I would use @{} in front and after the other columns to get rid of the extra space

• To make reading the table easier, I would add some additional vertical space between the blocks

• Are you abusing the poor X as multiplication sign? Don't!

• the syntax \tiny{...} is wrong. It is a switch and does not take an argument. Use {\tiny ...} instead.

• Missing math mode around the < signs

• most of your table should be in math mode to get correct minus sign and proper spacing around operators, but I'm too lazy to add this in the example below...

 \documentclass[10pt,english,8pt]{beamer}
\usetheme{default}
\usepackage{booktabs}
\usepackage{tabularx}

%\newcommand{\iid}{\stackrel{\mathrm{iid}}{\sim}}
\newcolumntype{C}{>{\centering\arraybackslash}X}
\newcolumntype{R}{>{\raggedright\arraybackslash}X}
\newcolumntype{L}{>{\raggedleft\arraybackslash}X}


\title{Beamer Template}
\author{TeXstudio Team}
\begin{document}


\begin{frame}{Frame Title}

    \begin{table}[htbp]
        %\begin{table}[!ht]
        \centering
        \scriptsize
        %\caption{Title }
        \label{tab:5}
        \begin{tabularx}{1\textwidth}
            {
                @{}
                >{\raggedright\arraybackslash}X
                >{\centering\arraybackslash}p{1.75cm}
                >{\centering\arraybackslash}p{1.75cm}
                >{\centering\arraybackslash}p{1.75cm}
                >{\centering\arraybackslash}p{1.75cm}
                @{}
            }
            %\multicolumn{11}{@{}p{1\textwidth}@{}}{\footnotesize 
                %   Caption }\\
            \toprule 
            
            & Log Probability of Default & Log Recovery Rate
            & Log Spread & Log Leverage  \\ [0.5ex] 
            & (1) & (2) & (3) & (4)  \\
            \midrule
            Log Damage 
            &0.017**    &-0.003***   & 0.002 & -0.157    \\
            &(0.0008)   &(0.003)   & (0.075) & (0.178)  \\\addlinespace
            Log Adaptation
            &-0.157***  &0.012  &-0.463** & 0.514*** \\
            &(0.021)    &(0.007)    &(0.182)    &(0.193)\\\addlinespace
            Log Damage $\times$ 
            &0.006  &0.018* &-0.398 &0.535 \\
            Log Adaptation &(0.030) &(0.011) &(0.249) &(0.513)\\\addlinespace
            Constant
            &-1.227***&-0.117***&2.244***&0.101\\
            &(0.026)&(0.009)&(0.187)&(0.237)\\                      
            \midrule
            Observations &926 &925 &458 &177 \\
            $R^2$ &41\% &19\% &8\%  &38\%\\
            Adjusted $R^2$ &40\%&17\%&4\%&32\%\\\addlinespace
            Residual Std. Error 
            & 0.071 &   0.025 & 0.373 & 0.264 \\
            & (df = 907) & (df = 906) & (df = 439) & (df = 159)\\\addlinespace
            F Statistic 
            & 35.253*** &   11.455*** & 2.104***  & 5.811***  \\
            & (df = 18; 907)&   (df = 18; 906)& (df = 18; 439)& (df = 17; 159)\\
            
            
            \bottomrule 
            \addlinespace
            \multicolumn{4}{@{}p{0.8\textwidth}@{}}{\footnotesize {\tiny Note: *$p<0.1$; **$p<0.05$; ***$p<0.01$ }} \\
        \end{tabularx}
        %\end{table}
    \end{table}
    
\end{frame}

\end{document}