The "Study Design" defines the overall structure of the study. Here, individual tasks are created or imported. These tasks are assigned to blocks in order to group related tasks (e.g., instructions and a behavioral study). Blocks can in turn be assigned to sessions in which the blocks are either displayed one after the other or their sequence is randomized. The study design also defines whether a distinction is made between different groups of subjects in the study and in which these differ. One or more sessions can be assigned to the subject groups to test a subject once or more. Video Link
Note: For a study to work correctly, at least one group with one session must exist. At least one block with at least one task should again be in this session.
A "task" is a single instance within a study in which the content is created. For example, a simple study could consist of the following tasks::
- Intro-Task (Explnation of the task)
- Main-Task (Interactive Task with several trials)
- Questionnaire-Task (short questionnaire about demographics)
- Outro-Task (Display of results).
Creation: A new task can be added via the "New Task" button and can be opened via the "Edit" button. An existing task within the study can be copied using the "Duplicate" function. A task from another study can be imported in the current study via the "ImportTask" button.
Assignment: In order for a task to be played in the right time in the experiment, it must be assigned to a block. Multiple assignments and repetitions of the same task, are possible.
Step by step
- Create a new task by clicking on "New Task".
- Give the task a unique name.
- Choose a canvas frame for a free design, or a page frame for a static questionnaire, and confirm with "Ok".
- Add the task in the "Blocks" column to a block via "Add Task".
- Use Drag & Drop to adjust the order of the task within the block.
- Open your task via "Edit" in the task editor to create it
A block comprises several tasks. The order of the individual tasks within a block is fixed. This is often useful to insure that instructions, a behavioral task and questionnaire are always shown in the same sequence.
A new block can be added using the "New Block" icon. Within a block, a task can be added to the block via the "add task" icon. All the tasks that have been created or imported in this study are available here. A task can be added several times. The order of tasks within a block can be changed via drag & drop.
Assignment: A block has to be assigned to a session.
A session represents a one-time participation of a subject in a study. Multiple blocks can be conducted in each session. This is useful for studies where several experiments or tasks are conducted and correlated with each other.
A new session can be added via the icon "New Session". Within a session, the "add block" icon can be used to add a new block to the session. All the blocks that were created in this study are available here. One block can occur several times per session.
Randomization: The sequence of the blocks can be defined via the settings icon. By default the sequence of blocks is set to be the same for all subjects (Fixed for all subjects). This sequence of blocks can be changed via drag & drop. Alternatively, the sequence of the blocks can be drawn randomly for each subject (Random Permuted Across Subjects), or balanced across subjects (Balanced Across subjects).
Time of participation: The time settings for study participation can be defined more precisely for each session, which is assigned to a group. Via the setting icon within a group, a certain point in time, or a time interval between the sessions can be defined for the session start. In the case of repeated measures, each participant gets automatically an e-mail invitation when the next session is ready to start.
Assignment: A session must be assigned to a group.
A group is the topmost instance in the student design. A study can also consist of several groups. Each group must have at least one session, but can also include several sessions. Groups with several sessions are useful, if the aim of the study is to repeatedly test the participants. Inclusion criteria can be defined for each group. So far one can make group assignment dependent on age, gender, mother tongue & country of origin. If a participant meets the participation criteria for several groups, the Group with the fewest participants so far (via server histogram) is selected for that subject. This guarantees an equal number of participants in the different groups. If a participant does not meet the criteria for participation for any of the groups, the subject cannot participate in the study.
A new group can be added via the icon "New Group". Within each group one can add a session via the icon "Add session". All the sessions that were created in this study are available here. A session can also occur several times in a group. The order of sessions within a group can be changed by drag & drop. During the data recordings, the order of the sessions is exactly the same for all subjects in one group (as shown in the study design). The menu for the participant inclusion criteria of the group can be opened via the settings icon next to the group.
The group settings offer various possibilities to integrate repeated measurements and different groups of participants into one study. The setup options for the start of each session can be opened separately for each assigned session (apart from the sessio settings itself). For each assigned session within a group, it is also possible to determine when this session can be started, i.e. when the participants can start the experiment.
The following settings are possible so far:
- Starting-Time anytime (default)
- Starting-Time specific time point
- earliest, date, time
- latest, date, time
- Starting-Time repeated:
- certain time point
- earliest, date, time
- certain day in the week
- earliest, week-day, time
- latest, week-day, time
- certain day in the month (1-31)
- earliest,day in the month (1-30), time
- latest,day in the month 1-30), time
- certain time point
- Starting-Time dependent on former session:
- earliest, days, hours, minutes (after completion of the former study)
- latest, days, hours, minutes(after completion of the former study)
The individual tasks and questionnaires of the study are designed in the task editor. On a canvas surface objects can be placed and resized freely using drag&drop. Questionnaires can be arranged on a page frame. Interactive changes of objects can be setup via the event system. The trial logic is created by adding factors and levels to the task, and by determining the nubber of trials per condition. In particular, different trials can have different object properties. Via the automatically or self created variables, data can be recorded.
Task-Settings & Main Functionality
The main functions are located at the top left corner of the task editor. In the "drop-down" Selection list one can directly switch between different tasks within the study. The save icon saves all current changes and the "Play" icon starts the current task in a test run.
Under Task Settings, some basic settings of the task can be setup. One can activate a countdown (3, 2, 1), which appears right before the start of the task on the center of the screen. Also the display mode can be selected. Here, the following options are possible here:
- Fullscreen Choosing this option the frames are zoomed in until a maximum size is reached either horizontally or vertically.
- Fixed Visual Degree If this option is selected, an external size calibration is carried out when starting the task. Here you can specify either the size of the screen in cm / inches or use a credit card or any type of check card to determine the size of the screen. The size of the frame then corresponds to the specified number in "visual degree" (central, with a screen distance of ~50 cm).
- Fixed in Millimeter Again, the screen is calibrated. However, the content is then fixed in millimeters.
- Fixed in Pixels This option fixes the size in pixels. The size corresponds to the chosen size in the task editor.
In the task editor, the trial system is located on the left side. In general, the trial system is used to create several repetitions (trials) of a task. The trial system consists of two parts, the "Factortree" and the "ConditionTable". When the "Factortree" is edited by the Experiment Designer (adding factors or levels), the "ConditionTable" is automatically updated based on the settings in the "Factortree".
In the Factor Tree the variation of the task is defined. This is done by creating:
- Trial Groups (Trials with a similar task structure)
- Factors (Type of variation)
- Level (Amount and characteristic of variation)
The trial-group is a group of trials within the task. All trials associated with this trial-group,
have the same basic structure (especially the same frames, objects and events). Using factors & levels one can setup variations of trials.
Multiple Trial Groups can be created if different types of trials (having different frames, objects, or events) should be carried out within the same task. Hence different frames, objects, and events can be created for each trial group. This is particularly useful for "catch trials".
Through the factors (treatments), the trials within a trial group are varied. Here, the factors define, which aspect of the object is to be varied, e.g. the position of an element, or the image category (which image is shown). For each factor, it is necessary to determine how many levels (expressions) this factor has and whether this factor is used for randomization / balancing (random factor) or not (fixed factor). For more information on randomization see the chapter on randomization.
The levels determine the characteristics of the factors. The factor "picture-category" could, for instance, have the three levels "houses, faces, cars". A condition is created for each level, which is displayed in the "Condition Table" at the bottom left. If several factors are created, each level of a factor is combined with all the levels of the other factors within the factor group (factors cross).
Usage: To define the influence of a level on the task, one can select the level in the Factortree and then create some variation on the drawing surface (e.g. moving some stimulus). These changes affect all trials and conditions in which the respective factors has the chosen level. This approach is particularly useful when a stimulus variation is dependent on the level of factor.
The factors and levels are directly combined and result in "Conditions" and "Trials", which are automatically displayed in the Condition Table at the bottom left of the editor. For each conditionAny number of trials can be defined. If a certain condition should not be shown the number of trials can thereby be set to 0.
The conditions are determined by the number of levels. In a multi-factor design,
the individual levels of the factors are combined. If there are, for instance, two factors
with three levels each, as a result we will get nine (3x3) conditions. Each condition will be initiated with the number of trials = 1.
Usage:To make changes to the individual conditions, one can click on, and thereby select, one condition in the Condition Table. The changes made apply only to the selected condition (i.e. all the the trials in that condition). Thereby, it is possible to adjust the interactions of the individual levels more precisely.
A trial is a single run of the task and thus the smallest unit within the trial system. Trials are subordinated to the conditions. Each condition is created by default with one trial. The number of trials per condition can be adjusted in the Condition Table.
Usage: If there are several trials within one condition, the condition can be opened (expanded) in the "Condition Table" and individual trials can be selected and consequently edited. These variations then only apply to this particular trial.
The default trial is located above the conditions for each trial group in the "Condition Table". Via the default trial, all trials within a trial group are selected ánd edited simultaneously. This can be used to define the rough overall task or trial structure. Any variations, which were made before are overwritten by changes in the Default Trial. Hence modifying the default trial resets all trials in a trial-group to the same "default" value.
Usage: It is most reasonable to place new elements first in the default trial and then adjust the variation, using the condition or trial selection.
- Setup the general task structure in the default trial by placing and setting objects on the drawing surface.
- Setup your factors and levels in the "Factortree". Name them appropriately to make later changes more easy to understand.
- Select a level in the Factortree and make changes on the drawing area that correspond to the level. Repeat this process for the other levels.
- Select a condition in the condition table and make the corresponding changes for the selected condition.
- Set the number of trials for this condition.
- To edit individual trials, expand the condition and select a single trial.
- To add or edit elements for the entire task, select the default trial again.
Generate trials automatically
The trial structure can also be created automatically via the file manager and the integrated multiselect function, especially if the variation is produced by different stimulus content (images, videos, sounds etc.). To do so, a container must be selected and the file manager must be opened via the folder icon in the properties panel. Several pictures/videos need to be selected and one has to click the "Assign" icon in the lower right corner. This opens the settings for choosing how to integrate these different files into the trial system. The following options are possible:
- The images/videos can be assigned to already existing trials, or new trials can be created within a specified condition.
- The images/videos can be assigned to existing conditions.
- 3. Factor Levels
- The images/videos can be assigned to already existing levels, to new levels within a specified factor, or a new factor can be created such that each level of the new factor is associated with one image/video.
Working with Trials
If factor groups, factors, levels, and conditions are setup with the right number of trials, the experimental content has to be assigned accordingly to different trials. Here it is of central importance to select the appropriate modification level. Overall, there are 4 levels of modification:
- Changes Only the selected trial.
- Changes all trials within the selected condition.
- Changes all conditions in which the selected factor possesses the selected level.
- Changes all trial with the selected trial group.
The randomization via the task editor regulates which trials are displayed to which subjects and in which order these trials will be presented. The randomization settings are located in the task editor in the left panel under the menu item "Randomization Settings". A click on "Edit" opens a dialog box, in which all relevant settings can be made.
Overall, there are 4 main settings, by which the selection and sequence of the trials will be determined. The menu item Trial Order (top left in the dialog) has the following options: "random", "fixed by design", "fixed by hand", "upload Trial Sequences".
Fixed by Design
Each subject will will be shown each trial exactly once. The trial order is as listed in the editor and the same for all subjects .
Fixed by Hand
This setting allows you to enter a sequence of the trails yourself. For this purpose the "Trial Id's" must be entered, which can be seen in the "Condition Table". Trials may also be repeated. For this sequence Trials Ids must be separated by a comma. The sequence is the same for all subjects.
Upload Trial Sequences
Here a CSV file can be uploaded. This allows you to specify different trial sequences for several subjects. Individual trials are separated by a comma, new subjects correspond to a new line (CR-LF).
To do the randomization within the Labvanced Task Editor, the option "random" must be selected. Hence if you select "random" some additional settings have to be made. These are explained in more detail below.
Under the menu item Condition Order, you can specify whether the individual conditions are presented block-wise (Define Order blockwise)
or randomly intermixed (Random).
If a block-wise display is selected, the sequence of the conditions can be the same for all subjects (fixed by design) or the sequence can be determined randomly for each subject. (unbalanced permutation).
If the conditions are displayed randomly, certain restrictions can be made. Especially it is possible to determine how often the same condition may repeat in a row.
The randomization by factors is a very important part of trial randomization. For each factor it will be determined whether this is a "fixed" or a "random" factor. While "fixed factors" define new trials, "random factors" allow for balancing of variations within trials. Thus, during the presentation of the task, all levels of all fixed factors will certainly appear, but for random factors only one level is drawn "randomly".
- “Random Draw with Cover” - Choosing this option, for each trial the factor level is chosen randomly among all available levels.
- “Balanced within Task” - All levels of the factor are drawn equally often over the whole task. However, the order of the levels is chosen randomly.
- “Balanced within other Factors”- This balances one factor within another one or within several other factors. If, for instance, the factor "position" is balanced within the factor "image content", then for each level of the factor "image content" the factor position is balanced (e.g. level=left and level=right appear equally often). A factor can also be balanced within several other factors, however, no circular dependencies may arise.
In both cases, different picture pairs of houses and faces should be presented.
Without a Random Factor:
A task with two fixed factors is created:
Factor 1: Image category - with the 2 levels: Houses & face
Factor 2: Correct image position with the 2 levels: Correct_right & Correct_Links
This results in 4 conditions. For each condition, 10 trials are setup to show different pairs of images for the respective picture categories. The 10 pairs of house images are displayed once in the condition with the level Correct_right and once in with the level Correct_left. As a result it will display the "correct" image once to the left and once to the right. The same applies to the pictures of the faces. In other words, each stimulus is displayed twice and a total of 40 trials are presented.
With a Random Factor:
In this example, the factor "Correct image position" is set to Random (Random Draw with Cover).
Thereby for each trial the level of the random factor "Correct image position" is chosen randomly between the two options "Correct Left" and "Correct Right". The "correct" image is thus presented randomly either to the right or to the left, so that each image is displayed only once. A total of 20 trials will be presented.
Trials Per Subject
This option is used to determine the number of trials per subject. The default setting is that all trials (after counting in random factors) are displayed to each subject. It is also possible to display fewer trials or more trials, using the option "Determine the amount of trials manually".
Resulting Conditions & Trials
To see if the selected settings are setup correctly, the overview shows how many conditions and trials remain, after the random factors were accounted for. In the "Variations" column, you can see how many variants (possible instances) a trial has due to the random factors.
Simulation of trial sequence
The second way to check the settings is through the simulated trial sequence. Based on the settings made, a possible trial sequence is calculated and displayed here. By clicking on the "Refresh" icon, this possible sequence is recalculated.
All experimental content that can be added to the drawing surface are called objects.
Objects can be added, copied, and deleted for the currently selected frame.
Objects can be added using the toolbar to the left of the drawing surface, an thereafter be selected
and edited. Changes to the objects can be made directly on the drawing surface (scaling, change in position)
or by using the "Object-Properties" panel on the right. In this panel, all properties of the currently selected object are displayed
and can be modified using the input fields.
Canvas objects: For the canvas frame, the display order (z-index) can also be setup to determine, which object is displayed in the front position and which appears behind it. This setting is indicated by the arrows in the object list on the right side of the editor. In addition, all objects can be dragged and scaled freely on the canvas frame.
Page objects: On a page frame, the elements are arranged automatically. The order of the elements can be changed on a page frame by clicking on the left handle using drag and drop.
All available objects are listed in the toolbar, left to the drawing surface. By clicking on toolbar icon, the corresponding object is added to the selected frame. All objects on the current selected frame are listed in the object overview at the top right corner.
The filemanager can be used to replace the picture placeholder-object with images have standard formats (e.g. jpg,png). In addition, there are options to determine how the image is inserted into the placeholder.
An audio file can be inserted via the audio object, which can be started and stopped by theEvent System or by the using the control display.
Videos can be inserted via the video object. Video should be encoded using the h264 codec. These can also be controlled via the event system or via control display.
Checkbox & Multiple-Choice
A question in which one or more answers have to be selected from several response options.
A question or statement where a tendency is indicated on a scale.
Several Likert scales arranged below each other, in which the labels of the scale can be labeled by hand.
A question with a small input field for individual words, numbers, or other type of input
A question with longer text area for answering.
A question with a slider as a response option.
A question with a drop down menu as answer option.
A question ans several text_inputs that can be sorted by the subject using drag and drop.
A standard button whose text can be edited and which can trigger events using the trigger "ButtonClick".
A prefabricated button set that is created with two events, allowing the subject to navigate to the next and to the previous frame.
A bar which can be used to display the progress of the experiment.
An invisible object that can be used to control events.
The event system can be used to setup complex functionality, logic and interactions in a task.
An event always consists of a trigger and one or more actions.
The events are setup in the Task Editor under the "Event" tab. New events can be created via a click on "New Event". All events on the current frame are then displayed in a list at the top right corner and their properties can be edited at the bottom right corner.
The trigger of the event defines when the event is triggered. This can be, for example, a mouse click on a particular object, a keyboard input but also it could be a specific time within the experiment or a change of a variable. All options and their settings are explained in the following list:
Trigger:Mouse-Click on a specific object
Settings:Action: Click, Press, Release, Hover
Mouse-Key: right, left
Target: Selection of Display Object
Trigger:Left Mouse-Click on a Button-Object.
Settings:Target: Selection of a button
Trigger:Key-Press on the Keyboard
Settings:Action: Key-Press, Key-Release
Buttons: Selection of a key on the keyboard
Trigger:Start of the frame
Trigger:End of the frame
Trigger:A Timer-Variable reaches it's time trigger value.
Settings:Selection of a variable
Selection of a time trigger value
Variable Value Changed
Trigger:Upon value change of a certain variable.
Settings:Selection of a variable
Trigger:Start, Stop or End of a Audio or Video File
Settings:Target: Selection of a Audio or Video File
Execute-Condition: OnStart, OnStop, OnEnd
The actions define what should happen when the event is executed. For instance, actions can be used to change variables and object properties, recorded data, and jump to the next trial or task. The actions are setup in the second step of the event dialog box. There may be several actions per event. For events that were already created the actions can be edited in the lower right corner of the event panel.
Set or Record Variable
Usage:Set a variable value,
By choosing the option, "record variable" the data can be stored for later analysis.
Settings:Auswahl der Variabel
Auswahl des neuen Wertes
Usage:Switch to the next frame, trial or task or to a specific frame.
Settings:Select where to jump to: next frame, trial, task, specific frame
Usage:Set an object property
Settings:Select the object and its property
Select the new value of that property.
Usage:Start, pause or stop audio and video elements
Settings:Select a Audio ot Video-Object
Action: Start, pause, or end of the video or audio
Draw Random Number
Usage:Draws a random number and saves the value in a variable
Random value between minimum and maximum Gaussian Distribution:
Random value by mean value & standard deviation
Usage:Executes sub-actions after a time delay to the trigger.
Settings:Select a Time Delay in milli seconds
Adding sub-actions to be executed.
Requirements are optional for creating an event, but are often helpful to define the event more precisely (e.g. execute different actions in different conditions).
Using Requirements, one can define logical expressions which must be fulfilled in order for the actions of the event to be triggered.
For each event several logical expressions can be added via "Add Requirement". Each logical expression consists of a value
(e.g. a variable or object property), a comparison character (e.g. equal or is greater than), and a comparison value
(e.g. another variable or a formula).
In addition, a tree structure can be built if an action is very specific and different logical expressions must be evaluated. A distinction is made between AND and OR groups.
AND group: All logical expressions in an AND group must be fulfilled for the action to be triggered.
OR group: At least one of the logical expressions within the OR group must be fulfilled for the action to be triggered.
- Numeric:A Numeric Value
- String:A String Array
- Boolean:A Boolean value (true,false)
- Object Property:Objects and their properties
- Variable: An existing variable or a new variable
- Arithmetic: A formula, in which other parameters can be inserted
- Event Parameter: Depending on Trigger
- Stimulus Name: -Mouse Event- Name of the trigger object
- Time from frame onset: Time since frame start
- Stimulus Info: The stimulus information of the trigger object. This can be varied per condition or trial
- Id of key: -Keyboard- keyboard key which triggered the event.
- New Value: -Variable Value Changed- Current value of the variable which triggered the event.
- Time of Audio/Video-Audio/Video Element- Current time of the audio or video.
Variables can be used to store actions of a participant, e.g. which answer is given to a question, which image was clicked, how long did it take. Variables may also be used to perform internal calculations, e.g the number of correct answers, or how many percent of the trials have already been completed. Some variables are created automatically. These are important for the construction of the experiment and the correct presentation.
The variables are displayed in the task editor under the "Variables" tab.
New variables can be created using "New Variable". These are then displayed in the list at the top right corner and can be edited at the bottom right corner.
An overview of all variables of a study can be found outside the task editor via the left navigation bar under the menu point "Variables".
All variables are basically "global" and available for the entire experiment. In other words one can access the same variable from different frames and tasks. This is useful when either two similar tasks are performed successively, but only one variable should exist in which the data are stored; or if a previously recorded variable is used in a successive task. For instance, this can be used to send feedback back to the participant If a variable is used in a particular frame, this variable is displayed in the variable list at the top right of the task editor.
Some variables are automatically created by our platform for the study (so-called system variables). These variables are important in order to ensure the correct presentation and for data export. However, these variables can often also be used in requirements; for instance, to run events only under certain conditions. We do not recommend that you change the system variables by yourself, as this often leads to serious errors.
Variables for Questionnaire Items
Variables are automatically created for all questionnaire objects. This ensures that the subjects' responses of questionnaire elements is saved automatically. For each questionnaire item/object is specified in which variables the information is stored. This information is displayed at the object properties panel under "Linked Variable", The red point indicates whether the variable is recorded ot not. Furthermore, here it is also possible to change the variable reference.
Variables are used in many events. To select a variable for some event one can either choose an existing variable or create new variable. Overall, the variable selection dialog contains three different tabs: "Local Variables", "Global Variables" and "New Variable". Under "Local Variables" you can see and select all the variables that are already used on the current frame. Under "Global Variables", all variables of the study can be seen and a new variable can be created under the "New Variable" tab. When creating a new variable you can also directly specify whether this variable should be recorded or not.
Questionnaire objects are automatically recorded. Recordings of any further user interaction or other information must be manually setup. Proceed as follows:
- Create a new Event.
- Define the trigger that determines when the value should be saved and click "Next".
- Select the "Set / Record Variable" action.
- Click on the "New Variable" tab (If you have already created a variable in which the values should to be stored, you can select it under Local Variables & jump to step 7).
- Give the new variable a suitable name (for example, response time) and, if necessary, make further settings for the data type and scaling.
- Ensure that the "Record variable" check box is set so that the variable will be recorded.
- Once a variable is created or selected, you can select exactly what you want to record by clicking the Edit icon.
Record a current object property (e.g. width, height, position etc.)
Record a current value of a variable.
This function can be used to create arbitrary interleaves (for example, variable_A = variable_A + variable_B).
This allows to record the response time.
Depending on the trigger, different information is available. For example, if the trigger was "Mouse Click", you can record the object name and the stimulus information of the object, which triggered the event.
Here, a constant can be recorded, e.g. a number, a string, or a boolean.
Each trial can contain several frames, which are presented during presentation typically one after the other.
There are two different frame types: canvas frames and page frames. On a canvas frame, objects can be freely placed, designed and scaled.
This allows you to edit canvas frames very individually.
Page frames are used in particular to create questionnaires, which can be designed very efficiently by a pre-defined layout.
All frames are displayed in the "Trial Timeline" (bottom middle) in the order in which they were added. The frame which was clicked on last is the current selected frame. The "properties" of the current selected frame are shown to the right of the Trial Timeline. The order of frames can be changed using drag&drop and existing frames can be can be copied. When copying a frame it is important to consider whether the variables used should be linked or whether new/independent variables should be created for the new (copied frame). Objects and events are always unique per frame. Frames can also be deleted by a click on the remove icon.
- Name: Name of the frame
- Enable Duration: Determines whether the frame has a fixed display duration so that the next frame is automatically displayed after the set time has elapsed (triggers next frame).
- Color: Background color of the frame
- Hide Mouse: Determines whether the mouse is hidden during the frame presentaion.
- Frame Width & Height: The Width & Height of the Frame in Design Units (Only for Canvas Frame).
- Max-Width: The maximum width of the frame in Design Units (For page frames only).
After the design of the study has been completed, it can be published under "Publishing". This makes it possible to share the studies in different ways. The study can be advertised in the LabVanced Library, a link to the study can be send to prospective subejcts per mail, or it can be shared on social media platforms. In addition, a large number ob subject can be recruited using our Crowdsourcing Feature . Of course, the study can also be published privately such that only selected subjects are able to participate.
Data View & Export
Data View & Export
Under the "Data View" icon, the recorded data can be viewed, managed and exported (downloaded). The data is displayed per recording session. Incomplete records can be filtered out. Single sessions or all sessions can be exported as CSV or XLS files.