\documentclass[slidestop,compress]{beamer}
\usepackage{graphicx}
\usepackage{boxedminipage}

% Set the theme
\mode<presentation>
{
	\usetheme{Darmstadt}
}

% Title, author, affiliation, and logo.
\title{Elections and Party Systems}

\author{Dan Pemstein}
\date{June 20, 2007}

\institute[University of Illinois]
{Department of Political Science\\
University of Illinois}

\pgfdeclareimage[height=1.0cm]{ui-logo}{/home/dan/media/images/logos/UILogoCL1c}
\logo{\pgfuseimage{ui-logo}}

\begin{document} % Start the actual presentation

% Automate the presentation of a highlighted TOC at the beginning of
% each section.

\AtBeginSection[]
{
	\begin{frame}
		\frametitle{Roadmap}
		\tableofcontents[currentsection]
	\end{frame}
}

% Produce a title slide
\begin{frame}
	\titlepage
\end{frame}

\begin{frame}
  \frametitle{The Research Question}

  \begin{itemize}
    \item How do democracies work?
    \item Why do we see variations in representations across countries
      and over time?
    \item Why do countries have different party systems?
  \end{itemize}

\end{frame}

\begin{frame}
  \frametitle{Operationalizing Representation}

  We want to explain variations in representation.  Can we narrow this
  down?

  \pause

  \begin{itemize}
    \item Number of parties
      \pause
    \item Ideological differences between parties
  \end{itemize}

\end{frame}


\begin{frame}
  \frametitle{Explaining the Number of Parties}

  We have two theories of the number of parties:

  \pause
  \begin{itemize}
    \item Institutional theory \\
      \begin{tabular}{lcl}
        I.V. & & D.V. \\
        Electoral system & $\rightarrow$ & \# parties
      \end{tabular}
    
    \pause
    
    \item Sociological theory \\
      \begin{tabular}{lcl}
        I.V. & & D.V. \\
        Social cleavages & $\rightarrow$ & \# parties
      \end{tabular}
  \end{itemize}

\end{frame}

\begin{frame}
  \frametitle{Electoral Systems}

  \begin{itemize}
    \item District magnitude
      \pause
      \begin{itemize}
        \item Single member districts (SMD)
        \item Multi-member districts (MMD)
      \end{itemize}
      \pause
    \item Electoral formula
      \pause
      \begin{itemize}
        \item Plurality (FPTP)
          \pause
        \item Majority (Runoff, AV)
          \pause
        \item Proportional representation (List PR, STV)
      \end{itemize}
  \end{itemize}
\end{frame}

\begin{frame}
  \frametitle{Votes and Seats}

  \begin{center}
    \includegraphics[height=1.5in]{figures/dm1}
  \end{center}

  \begin{columns}
    \uncover<2->{
      \begin{column}{2in}
        Proportional Representation
        \begin{itemize}
          \item A: 122 seats (41\%)
          \item B: 115 seats (38\%)
          \item C: 63 seats (21\%)
        \end{itemize}
      \end{column}
    }

    \uncover<3->{
      \begin{column}{2in}
        Single Member Districts
        \begin{itemize}
          \item A: 200 seats (66\%)
          \item B: 100 seats (33\%)
          \item C: 0 seats (0\%)
        \end{itemize}
      \end{column}
     }
   \end{columns}

\end{frame}

\begin{frame}
  \frametitle{Votes and Seats}

  \begin{center}
    \includegraphics[height=1.5in]{figures/dm2}
  \end{center}

  \pause

  \begin{columns}
    \uncover<2->{
      \begin{column}{2in}
        Proportional Representation
        \begin{itemize}
          \item A: 102 seats (34\%)
          \item B: 99 seats (33\%)
          \item C: 63 seats (21\%)
          \item D: 36 seats (12\%)
        \end{itemize}
      \end{column}
    }

    \uncover<3->{
      \begin{column}{2in}
        Single Member Districts
        \begin{itemize}
          \item A: 100 seats (33\%)
          \item B: 100 seats (33\%)
          \item C: 0 seats (0\%)
          \item D: 100 seats (33\%)
        \end{itemize}
      \end{column}
     }
   \end{columns}

\end{frame}

\begin{frame}
  \frametitle{Back to Explaining the Number of Parties\ldots}

  \begin{tabular}{lcl}
    I.V. & & D.V. \\
    Electoral system & $\rightarrow$ & \# parties
  \end{tabular}

  \pause

  \begin{itemize}
    \item Majoritarian SMD elections $\rightarrow$ 2 party competition
    \item MMD PR allows multiparty competition
  \end{itemize}

  \pause

  What's the causal mechanism?

  \pause

  \vspace{.25cm}
  Under majoritarian SMD:
  \begin{itemize}
    \item Voters are strategic and don't want to waste votes on a
      loser
    \item Politicians are strategic and coalesce into two parties
  \end{itemize}
\end{frame}

\begin{frame}
  \frametitle{The Effective Number of Parties}

  How do we operationalize the dependent variable?  Specifically, how
  do we deal with small parties?

  \pause

  \vspace{.25cm}
  We use the effective number of parties:
  \[ N = \frac{1}{\sum_i s_i^2} \]


  \pause

  \begin{itemize}
    \item Ignores parties that don't get into legislature
    \item Weights parties by strength
  \end{itemize}
\end{frame}


\begin{frame}
  \frametitle{Example: U.S. House Elections 2006}
  
  \begin{tabular}{lll}
    Party & Vote \% & Seat \% \\
    \hline
    Democrats & 52.0 & 53.6 \\
    Republicans & 45.6 & 46.4 \\
    Independents & 0.7 & 0.0 \\
    Others & 1.7 & 0.0 \\
    \hline
  \end{tabular}

  Effective number of parties = 1.99

  \vspace{1cm}
  \begin{itemize}
    \item 435 SMDs
    \item Plurality rule
  \end{itemize}
\end{frame}

\begin{frame}
  \frametitle{Example: U.K Legislative Elections 2005}

  \begin{tabular}{lll}
    Party & Vote \% & Seat \% \\
    \hline
    Conservative \& Unionist & 33.2 & 32.0 \\
    Labour & 35.2 & 55.1 \\
    Liberal Democrats & 22.1 & 9.6 \\
    Other & 9.5 & 3.3 \\
    \hline
  \end{tabular}

  Effective number of parties = 2.40

  \vspace{1cm}
  \begin{itemize}
    \item 646 SMDs
    \item Plurality rule
  \end{itemize}

\end{frame}

\begin{frame}
  \frametitle{Example: Canadian Legislative Elections 2006}

  \begin{tabular}{lll}
    Party & Vote \% & Seat \% \\
    \hline
    Conservatives & 36.3 & 40.3 \\
    Liberals & 30.2 & 33.4 \\
    New Democrats & 17.5 & 9.4 \\
    Quebec Bloc & 10.5 & 16.6 \\
    Other & 5.5 & 0.3 \\
    \hline
  \end{tabular}

  Effective number of parties = 3.21

  % Note: all 51 Quebec bloc cands were elected in Quebec

  \vspace{1cm}
  \begin{itemize}
    \item 308 SMDs
    \item Plurality rule
  \end{itemize}

\end{frame}

\begin{frame}
  \frametitle{Example: Dutch Legislative Elections 2006}

  \begin{columns}
    \begin{column}{2in}
  \begin{tabular}{lll}
    Party & Vote \% & Seat \% \\
    \hline
    CDA & 26.5 & 27.3 \\
    CU & 4.0 & 4.0 \\
    D66 & 2.0 & 2.0 \\
    GL & 4.6 & 4.7 \\
    LPF & 0.2 & 0.0 \\
    PvdA & 21.2 & 22 \\
    PvdD & 1.8 & 1.3 \\
    PVV & 5.9 &  6.0 \\
    SGP & 1.6 & 1.3 \\
    SP & 16.6 & 16.7 \\
    VVD & 14.7 & 14.7 \\
    Others & 1.0 & 0.0 \\
    \hline
  \end{tabular}

  Effective number of parties = 5.54
  \end{column}

  \begin{column}{2in}
  \begin{itemize}
    \item 1 MMD (150 seats)
    \item List PR
  \end{itemize}
  \end{column}
  \end{columns}

\end{frame}

\begin{frame}
  \frametitle{Testing the Theory}

  \begin{center}
    \includegraphics[height=2.9in]{figures/lijpparties}
  \end{center}

\end{frame}

\begin{frame}
  \frametitle{Majoritarian or PR?}

  \begin{itemize}
    \item Vote share vs seat share (fairness)
    \item Minority representation 
    \item Dealing with serious cleavages
    \item Representation and efficiency
  \end{itemize}
\end{frame}

\end{document}