• A server (the Tree) controls a client (the Leaf)
  • The experimenter's machine is the Tree
  • The participant's machine is the Leaf
• The server sends pieces of information to the client(s) → output
• The server collects pieces of information from the client(s) ← input

1. Copy the ztree.exe into your FOLDER
2. Copy the zleaf.exe into your FOLDER
3. Create a link to zleaf.exe (copy → paste shortcut)
4. Rename it "Client01"
5. Right click → Properties → Destination → "\PATH TO FOLDER\zleaf.exe" /name CLIENT01 /server IP OF SERVER ...
6. Or create a batch le (clients.bat) with the following commands
   • start zleaf /name CLIENT01 /server IP ADDRESS OF THE SERVER ...

• Define here the basic features of the experiment
  • Number of repetitions
  • Number of participants

• Stage
• Containes the code for each expeirmental stage
• Box
  • Defines the type of information presented on a screen
• Item
  • The information provided/collected from the participant

• Each stage must have a unique name
• Start
  • Wait for all
    • The stage is accessed by all participants together
  • Start if possible
    • Each participant accesses the stage when ready
  • Start if ...
    • Access to the stage is conditional upon an event

• Leave stage after timeout
  • If no input
    • After the timeout spcified in the box the stage is automatically left ONLY if there is no input
  • Yes
    • The stage is automatically left after the timeout
  • No
    • The stage is never left automatically

• The first step is to organize the screen
  • Information
  • Data input
  • Data output
• Boxes are a convenient way to "split" the screen

• Boxes are employed to contain pieces of information
• Several kinds of boxes are available
• Standard box is the most commonly used

• The Standard Box is useful to deliver/collect pieces of information
  • Like all other boxes it can be displayed when certain conditions are met (Display condition)
  • The default is to always display it

• The Header Box delivers information about the progress of the experiment
  • Current period out of total periods (repetitions)
  • Seconds left to choose in the current Stage

• The Grid Box helps organize content that has a column/row organization
  • e.g., simultaneous games

• The Plot Box allows to draw graphs
  • It is a $R^2$ space

• Basic element to collect/provide information
  • Label contains the text associated to the variable
  • Variable is the name of the input/output variable
  • Layout is the "style" of the variable
    • Input must be flaggeds to specify that it is an input variable

• The standard font is quite small and plain
• The output can be "beautyfied" via \rtf code
  • Bold, Italic, Right-aligned, Centered
  • Different sizes

• To collect values one needs to flag the "Input" field
  • The Maximum and Minimum values must be defined
• Default value
• Show Value (flag)
• Empty allowed (flag)

			 1
		 

			 !text: 1="one"; 2="two"; 3="three";
			 

		 !radio: 1="one; 2=two"; 3="three";
			 

	 !radioline: 1="one"; 3="three";3;
	 

			 !radiosequence: 1="one; 2=two"; 3="three";
		 

			!slider: 1="one"; 3="three";3;
			 

		 !scrollbar: 1="one"; 3="three";3;
			 

	 !checkbox: 1="one; 2=two"; 3="three";
	 

	 !button: 1="one; 2=two"; 3="three";
	 

• Buttons are used to move to next stage
  • If the screen has an input is it recorded

• Tables are used to "store" values
• The default table is "subjects"
  • It contains the values of each particiopant
• Other tables can be used to
  • Define common variables for all participants (e.g., globals)
  • Store variables across periods
  • Collect relevant values for the subsequent analysis

• When creating a new Table one can specify
  • Lifetime
    • Either a period, the treatment or the entire session
  • Program execution
    • When first enters, everyone or last

• Programs are used to input an order before the start of a stage or in correspondence to an action (e.g., button click)
  • As an example, a program can be used to define participation to a stage

  • 	// The stage is accessed only in periods following the first period
    
     			 Participate=if(Period>1,0,1)	 

• Specify the table in which the program is executed
  • The default is subjects table
  • The execution of the software can be conditioned upon some condition