&\textbf{H1}& Lower key actuation force improves typing speed over higher key actuation force and therefore enhances efficiency. &\\
&&&\\
&\textbf{H2}& Higher key actuation force decreases typing errors compared to lower key actuation force, which improves efficiency. &\\
&&&\\
&\textbf{H3}& Keys with lower actuation force are perceived as more satisfactory to write with then keys with higher actuation force. &\\
&&&\\
&\textbf{H4}& Users perform better and feel more satisfied while using Keyboards with personalized/adjusted key actuation force then without the personalization/adjustment. &\\
\end{longtable}
\section{Proposed Method}
\subsection{Subjects}
Main target group to recruit participants for the research study from are
personal contacts and fellow students. It is planned to recruit ~20 participants
in total. Participants are required to type with more than just one
finger. Therefore touch typing is not a mandatory but helpful skill to
participate. The age distribution for the subjects is estimated to be between 18
and 56 years. The average typing speed should be known prior to the main
experiment. Therefore, a typing speed test should be performed on the subject's
own keyboard beforehand. This pre experiment typing test has to be performed
within the standardized test environment consisting of an adjustable chair,
desk, monitor and the typing test software used within the main experiment.
Also, all subjects have to give their written consent to participate in the
study.
\subsection{Study design}
The experiment should consist of a experimental group and a control group. The text used for the typing test should be easily understandable. Therefore the text has to be evaluated with the help of a Flesch-Kncaid scala (understandability of text).
% ASK: Should there be a control group at all, if so should they use their own keyboard or always the same random keyboard while they think they are testing different keyswitches?
\textbf{Planned experiment procedure:}
\begin{enumerate}
\item Pre-Test questionnaire to gather demographic and other relevant
information (age, gender, dominant hand, touch typing experience, average
\gls{KB} usage per day, previous medical conditions affecting the result of
the study -> \gls{RSI}, \gls{CTS}, etc.) (5 min)
% ASK: Medical conditions OK?
\item Adjustment of test environment (Chair height, monitor height, etc.) (2 min)
\item Familiarization with the typing test (5 min)
\item\textbf{Main-Test part 1 (H1-H3):} Typing tests (2x 5 min per \gls{KB} +
5 min break in between tests) with different actuation forces for the whole
keyboard (35 \gls{g}, 50 \gls{g}, 80 \gls{g}). These specific values are the
results of a self conducted comparison between the product lines of most major
keyswitch manufacturers. The results show, that the lowest average force for
keyswitches available is 35 \gls{g}, the highest average force is 80 \gls{g},
and the most common offered force is 50 \gls{g}. The keyboard has an ISO type
and QWERTZ layout to match the subjects day-to-day layout and keyboard
format. The keyboard uses mechanical keyswitches which are hot-pluggable and
therefore can be changed after each typing test while participants take a
break. The order for the keyswitch actuation forces and texts for the
individual tests is randomized and across subjects counterbalanced to mitigate
order effects \cite{statist_counterbalancing}. \textbf{(total: 60 min)}
\begin{enumerate}
\item First typing test (15 min)
\item Change of keyswitches + follow-up ISO keyboard comfort questionnaire (ISO9241-410) (5 min)
\item Second typing test (15 min)
\item Change of keyswitches + follow-up ISO keyboard comfort questionnaire (ISO9241-410) (5 min)
\item Third typing test (15 min)
\item Follow-up ISO keyboard comfort questionnaire (ISO9241-410) (5 min)
\end{enumerate}
\item\textbf{Main-Test part 2 (H4):} Another typing test to compare the
results of keyboards with uniform actuation force to keyboards with adjusted
actuation force per finger/key. \textbf{(total: 50 min)}
\begin{enumerate}
\item Typing sample text on an analog keyboard with high actuation force (150
\gls{g}) to measure difference in typing force per finger and key. The subject
should be forced to press every relevant key (letters, digits, common special
characters) at least 5 times (can be replaced by a keyboard that is equipped
with different zones of keyswitches that use appropriate actuation forces) (30
min including adjustment of keyboard and familiarization)
\item Typing speed tests on the adjusted keyboard (15 min) with follow-up ISO
