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\begin{center}
{\Huge \textsc{NGI POINTER: GNU Taler UX Study}}
\end{center}

\section{Context}

For the NGI POINTER programme, the GNU Taler team developed
age-restricted payments and P2P payments, which were supposed
to be evaluated in a usability study to gather feedback and
inform further development.

The BFH ``Digitaltag'' is an annual day-long event where the
university presents itself to the public. It is held right next to the
central train station of Biel/Bienne, and is open to the general
public.  It was attended by a mixture of prospective students, normal
adults, Swiss executives and retirees.

We used the opportunity to both present GNU Taler to the public, and
to conduct usability studies with interested volunteers.

\begin{figure}[h!]
  \includegraphics[width=\textwidth]{digitaltag-ux-setup.jpg}
  \caption{Our booth, with GNU Taler publications (including on
    age-restrictions), NGI stickers, and a Taler-enabled coffee machine.}
\end{figure}


\section{Preparation}

We prepared several notebooks with a browser running a Taler wallet as
well as several Android phones with a the Taler Android wallet.  We
setup the coffee machine and three Taler backends, one for CHF (used
by the coffee machine), one for KUDOS (used with age-restrictions in
the browser-based setup) and one for Bitcoin (used for P2P payments).
We also prepared a rough write-up describing what we would like users
to do.  These intended user stories are included in the appendix.  We
note that during the day, we permitted participants to deviate from
the script if they desired to do so, sometimes leading them to explore
other GNU Taler features (and us learning interesting lessons about
those).

For the UX study, we prepared four tables: two tables with the coffee
machine and information materials, and two tables with additional
chairs for guests for the actual UX experiment.

\begin{figure}[h!]
  \includegraphics[width=\textwidth]{digitaltag-ux-chairs.jpg}
  \caption{Tables for the UX study with Prof. Benoist.}
\end{figure}

\section{Data collection}

We did not collect any PII on the participants.\footnote{Except for
one executive who had come just for our booth from Zug and who gave us
his business card as he hopes to collaborate with us in the future.}
Instead, each team member wrote down their observations.  We
afterwards deduplicated the observations and turned those that could
lead to improvements into over 20 new issues on the GNU Taler
bugtracker (\#7334--\#7354).

\section{Key conclusions}

The day revealed the existence of several previously unknown bugs
(like refresh not working properly with the new features) as well
as quite a few surprising difficulties of users (not finding the
QR code button, not finding the account balance, not understanding
that the ``shop.demo.taler.net'' page is the shop where they should
buy things). We will try to rectify those as soon as possible.


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