Getting started with classEx

What you need

classEx is an online tool which runs centralized at the servers of the University of Passau. Therefore, no installation of software and no download of applications is necessary. Running games and developing games is done in a standard internet browser.

Lecturers and participants only needn a mobile device with an internet connection and an up-to-date browser. We suggest to use Firefox. Make sure that javascript is enabled and cookies are allowed (normally this is a default setting in many browsers). Do not use Internet Explorer for using classEx because classEx does not run with it.

For using classEx the lecturer only needs to register in order to get login credentials.


Participants do not need to register but can access classEx with the course password provided to the lecturer with the login credentials.

In order to get login credentials, please fill in the registration form at

For registration you have to provide your name, an email address and information about your institution. In addition, you have to confirm that you accept the terms of use and the data privacy policy. Please try to provide an institutional email address so that we can verify your affiliation. Registered users receive an email with login credentials. Login credentials are normally sent within 1-2 days. If you do not receive credentials after 2 days, please contact us at

Each user has an account (called course in classEx) which is linked to their institution. With the login credentials you obtain the right to use classEx for teaching, education, research and other purposes (for details please see terms of use).



The website shows the login for lecturers and participants.


Select the institution you named during your registration, typically your university.


Select your course or another course you have access to.

User types
  • Participants: They can participate interactively in a lecture or a presentation by logging in as a participant. They do not need to register and remain anonymous. They select the university and the course from the lecturer’s registration. The lecturer provides the course password. Participation after logging in is self-explanatory and does not require any previous knowledge.

  • Lecturer: Registered lecturers who have received a password can login as experimenter/lecturer. As lecturer you can organize your account, start ready-made games and quizzes, adapt them to your liking or create new ones. This documentation mainly explains the possibilities and options classEx offers for lecturers.

  • Administration: Individuals entrusted with the payoff can enter the administration mode in order to disburse the monetary payoff. This task can be delegated to a trustworthy person by the lecturer. You can find further instructions in Disbursal of payoffs.


A registered lecturer has received a password upon registration. This password can also be used for the administration user type. Participants are provided with their password by the lecturer (under Participants password you see how to change it and what to do if the participants password is lost).

A short overview

As the video shows, entering classEx as a lecturer offers three modes: overview mode pic_overview, lecture mode pic_lecturemode and editing mode pic_editmode. After login, the screen shows the overview mode. Here you can organize your games and access all important features of classEx. In the lecture mode you can run games, in the editing mode you can develop your own games.


In the top right-hand corner you find the main navigation bar which is always displayed in every mode. This allows you to switch from one mode to another and access your personal data.

The currently active mode is marked by a darker shade around its symbol pic_overview, here the overview mode. The left symbol pic_lecturemode takes you to the lecture mode. The right symbol pic_editmode takes you to the editing mode. The drop down menu (which shows the name of the lecturer and is shaded in black in the figure above) provides access to your personal data and your course data as well as the terms of use, the documentation, some general info on classEx and the log out button. More information on how to change your personal data can be found at Personal data and how to change your course data at Course data.

The different functionalities of copying, deleting,… are explained in the section Game.

The top bar is located in the top left corner. It is different in each mode. There you can find the main function for each mode. The details are explained in the respective section (lecture mode = Run ready-made games Settings in the top bar, overview = Organize your games Settings in the top bar, editing mode = Develop your own games Settings in the top bar).


This chapter clarifies the usage of some terms in this documentary. It can be used to look up terminology and can be skipped on first reading.


The person conducting a game is the lecturer. The lecturer starts games, starts new rounds, ends games and shows results. The lecturer controls the lecture screen that is visible to all participants (typically via a projector in the lecture hall).


Participants participate in games. All a participant needs for participation is a mobile device with internet access. No download is required. Sometimes participants are also called players.


A session is a sequence of games in a lecture, meeting or presentation. Participants should not shut their browser during a session.


After the end of a session, you can use statistical tests to analyze whether there is a relationship between the different games of a session. For example, you can examine whether participants with higher mathematical abilities are more risk averse. For this purpose, participants’ ID-numbers are stored in an Excel sheet.


Games consist of a sequence of stages. A game is typically characterized by a joint evaluation of the decisions and results at the end.


If you want to conduct a quiz consisting of several questions with unrelated results, it is advisable to create a separate game for each question.


Games consist of several stages. There are at least 2 stages: one for the decision input and one for the result output. Stages are ordered sequentially and are meant to be synchronization points in the game. Synchronization means that for the next stage to begin, all elements of the previous stage must have been finalized. Stages can be configured with several options. You can find more information here.


Elements are the modules of each stage. A stage has two areas in which you can add modules: participant and lecturer. You can chose from text elements, input elements (numerical input, likert scales, …), program code elements and output elements (histograms, bar charts, …). These can be combined and arranged as you like.


Treatments allow you to treat participants differently throughout a game. You can assign participants to treatments and customize stages and elements for treatments.


Many games require different roles of participants, e.g. producers and consumers. Stages and elements of a game can be customized according to the role of a participant.


Active participants of a game can be sorted into groups, e.g. according to their role, internal ID, randomly or a combination of these.

Assignment and Matching

Assignment and matching refers to the procedure of how participants are assigned into treatments, roles and groups at the start of a game. Further, you can choose how you want to rematch participants at the beginning of each round if you play more then one round.

Round and Loop

The number of rounds a game should be played can be defined. The loop refers to the stages of a game that should be repeated in every round. The loop is defined by selecting a starting stage and ending stage and the number of rounds.

Internal ID

ClassEx creates a unique internal ID for each subject that logs in. This ID is generated randomly and does not allow any inference about the identity of the subject. Therefore, subjects are completely anonymous in classEx by default. The internal ID serves as a mean to be able to analyze the data and compare behavior of subjects across different games if you play several in one session.

External ID

On login, participants can be asked to provide an external ID (e.g. their matriculation number). The external ID can also be provided with the link for automatic login. Please make sure that you elicit external IDs in accordance with data privacy regulations as the lecturer is responsible for this during data collection (see terms of use).

Subject ID

Subject IDs are used only within a game. Each participant gets an ID from 1 to the total number of participants. The first participants gets the Subject ID 1, the second participant the Subject ID 2, and so forth.

Global and subjects variables

Global variables are variables on the game level. They have the same value for all participants (e.g. an exchange rate). Subjects variables are variables on the subject level. The value of a subject variable is calculated separately for every participant (e.g. individual payoff).


Parameters are global variables that are adjustable before running a game (e.g. the endowment). Parameters can be changed directly in the lecture mode. They have the same value for all participants.

Global and subject program code elements

Many games require calculations or algorithms. These are created in program code elements. The programming language used in these elements is PHP. Global program code is utilized for calculations on the game level. Subject program code is utilized for calculations on the subject level (for every participant).