ich versuche folgende Graphik nachzubasteln in Latex:

Ich habe folgenden Code dazu gebastelt:
\documentclass{article}
\usepackage{tikz}
\usepackage{amsmath}
\begin{document}
\begin{tikzpicture}[
    node distance=1.5cm and 2.5cm,
    every node/.style={draw, rectangle, align=center, rounded corners},
    pre/.style={->,>=stealth',thick,draw=black!50},
    post/.style={->,>=stealth',thick,draw=black!50}
]
\node (research) [text width=4cm, fill=white] {Research design};
\node (traditional) [below left=of research, text width=3cm, fill=blue!20] {Traditional class};
\node (flipped) [below right=of research, text width=3cm, fill=blue!20] {Flipped class};
\node (pretest) [below=of research, text width=5cm, fill=white] {Pre-test algebra proficiency\\ Pre-test self-efficacy};
\node (training) [right=of flipped, xshift=-1cm, text width=3cm, fill=white] {Training sessions on the flipped approach};
\node (traditional_lessons) [below=of traditional, text width=3cm, fill=blue!20] {Traditional lessons};
\node (flipped_lessons) [below=of flipped, text width=3cm, fill=blue!20] {Flipped lessons};
\node (survey) [right=of flipped_lessons, xshift=-1cm, text width=3cm, fill=white] {Post-treatment survey};
\node (posttest) [below=of pretest, text width=5cm, fill=white] {Post-test algebra proficiency\\ Post-test self-efficacy};
\node (interview) [below=of posttest, text width=4cm, fill=white] {Teacher interview};
% Arrows
\draw[pre] (research) -- (traditional);
\draw[pre] (research) -- (flipped);
\draw[pre] (traditional) -- (pretest);
\draw[pre] (flipped) -- (pretest);
\draw[pre] (flipped) -- (training);
\draw[pre] (training) -- ++(0, -2) -| (pretest);
\draw[pre] (pretest) -- (traditional_lessons);
\draw[pre] (pretest) -- (flipped_lessons);
\draw[post] (flipped_lessons) -- (survey);
\draw[pre] (traditional_lessons) -- (posttest);
\draw[pre] (flipped_lessons) -- (posttest);
\draw[pre] (posttest) -- (interview);
% Text Annotations
\node at ($(pretest) + (-4, 0)$) {Weeks 1 + 2};
\node at ($(traditional_lessons) + (-4, 0)$) {Weeks 3 to 8};
\node at ($(posttest) + (4, 0)$) {Week 9};
\end{tikzpicture}
\end{document}VG & Danke
AP

