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The FLUD format: Logging Usability Data
from Web-based Applications

John Cugini / cuz [at] (cuz[at]nist[dot]gov)
Information Technology Laboratory
National Institute of Standards and Technology (NIST)
Gaithersburg, MD 20899
December 22, 2000

Contribution of the National Institute of Standards and Technology. Not subject to copyright. Reference to specific commercial products or brands is for information purposes only; no endorsement or recommendation by the National Institute of Standards and Technology, explicit or implicit, is intended.


This paper presents a proposed format for representing the behavior of users as they interact with a Web-based application. The captured log data can be valuable for analyzing and improving the usability of such applications. The background and motivation of this effort are briefly described. The detailed syntax and semantics of the format are then defined.


logging data; usability testing; web-based applications;

1. Background and Motivation

For the past three years, the Information Technology Laboratory of the National Institute of Standards and Technology (NIST) has been engaged in a project called NIST Web Metrics whose objective is to develop tools and techniques to support the evaluation of the usability of websites. One of our areas of interest is recording the behavior of users as they attempt to perform given tasks during interaction with a Web-based application. The captured log data can be valuable for analyzing and improving the usability of such applications.

It soon became evident this log data is quite complex and that a common file format is needed to allow various software components (such as recorders, parsers, analyzers, and visualizers) to exchange information. The goal then is to establish a Framework for Logging Usability Data - hence: "FLUD".

2. Design Issues

2.1 Event Model

The FLUD format embodies a mid-level abstraction of user activity. Behavior such as clicking a mouse usa-button, filling in a text entry, jumping to a new page, and toggling a checkbox is represented directly. The intention is that the FLUD model be general enough to encompass events reported from typical browsers, such as Netscape and Internet Explorer.

2.2 Scope

Although targeted at web applications, this format encompasses user interactions with other levels of the system. In particular, common operations performed by the browser and window system are defined, as well as those performed directly within a webpage. To the user and usability engineer, the former can be just as significant as the latter; their capture, however, may pose a challenge to generators, but if such interaction can be captured, this format provides a standard way for that information to be reported.

It is important to note that we are defining a file format only - the syntactic elements and their meaning. We are not in any way specifying the operation of the software components that may read or write FLUD files. Note also that this specification defines how an event is represented, but does not thereby require that all or any such events actually be detected and reported.

This first version of FLUD does not provide a direct representation of multiple frames within a window. We are studying how best to incorporate frames in later versions. See the description of Window_ID under Events for a recommendation on how to treat frames.

2.3 Basic File Structure

The basic structure of the file is that it contains general information about the session first in the loghead record, followed by blocks of task data or questionnaire data or individual events. Tasks can contain events or questionnaires. And finally, questionnaires contain responses. Notes from the subject or tester or others can be reported wherever events are legal. Here is a diagram of the constraints on the nesting structure:

Logfile ----------- / | \ / Task \ / / \ \ / / \ \ / / \ \ -------- Questionnaire Events, | Notes Response

2.4 Naming Convention

It is recommended that logfiles conforming to this specification be named with a file suffix of "ulog", e.g. "session37.ulog".

3. Conformance

Several levels of conformance for logfiles are defined, involving both syntax and semantics. Although this specification contains some comments about the recommended properties of logfile generators and interpreters, we do not define conformance for such software.

A file conforms syntactically if it can be parsed according to the rules in the grammar section. The rules include the context-free grammar, context-sensitive rules, and explanation of unresolved non-terminal symbols.
Defined Syntax
A file conforms to the defined syntax if it conforms syntactically and it contains no Ad_hoc elements. Thus, such a file can be parsed using only the defined grammatical fields. Generic interpreters should be able to completely analyze such a file.
Semantically true
A logfile is semantically true iff
  1. it conforms syntactically
  2. all the tasks, questionnaires, events, and notes represented in the file actually occurred as described
  3. all the Ad_hoc elements represented in the file actually occurred as described, according to the semantic meaning implicit in the file generator
  4. all the identifier elements in the file serve as identifiers: there is an accurate one-to-one mapping between these syntactic elements and the entities within the session that they purport to name.
The idea here is that everything the file is asserting about reality actually happened, even though there might be omissions ("The truth and nothing but the truth, but not necessarily the whole truth"). For defined elements, their meaning is established by this specification. For ad hoc elements, their meaning is established by the generator: it must define what it intends if it says, e.g. "glorp=2". Identifiers must be unambiguous, i.e. it is impermissible to have two names for the same entity, or the same name for two distinct entities.
Semantically state-complete
A file is semantically state-complete if it is semantically true and if all defined events that actually occurred in the session are recorded in the file, except those that involve some continuous operation, namely: pointer_moves, intermediate positions for scrolling and sliders, intermediate states of window moving and re-sizing, and six_DOF (degree of freedom) adjustments.
Semantically complete
A file is semantically complete if it is semantically true and if all defined events that actually occurred in the session are recorded in the file.

Note that checking semantic conformance is a fairly difficult task. But this difficulty follows from the fact that the logfile purports to be a description of the real-world behavior of a user of some software system. Semantic conformance necessarily involves some comparison between that description and the real-world events that are its subject.

4. Specifications

The specification sections describe:

Each logfile record is a sequence of fields, which are separated by spaces. Thus, any spaces within a field must be quoted, "like this". The general format for each record is:

Recordtype Mandatory-simple Mandatory-defined Optional-defined Ad-hoc

  • The Recordtype declares what kind of a record this is, e.g. "loghead", "event", "taskend".
  • Mandatory-simple fields come next and are unlabeled values.
  • Mandatory-defined fields follow, and are labelled with defined keywords (e.g. widget=abc).
  • Optional-defined fields follow, and are labelled with defined keywords but of course they need not be present.
  • Ad-hoc fields come last - they are arbitrary keyword-value pairs.

The formal grammar presented below uses conventional symbols:

* == 0 to infinity occurrences + == 1 to infinity occurrences ? == 0 to 1 occurrences | == or () == group syntactic elements

Variables (non-terminals) are capitalized, terminal symbols are lowercase or "Quoted". Comments (usually context-sensitive constraints) are [in brackets].

Specification: Logfile


Logfile == Log_header Log_block* Log_end [all times within the file must be in weakly ascending order.] Log_header == loghead Begin_time subject=Subject_ID version=Log_version time_zone=Time_zone Generator_ID? Browser_hardware? Browser_software? Tester_ID? Procedure? Session_set_ID? Ad_hoc_region Log_end == logend End_time Ad_hoc_region Begin_time == Time_value End_time == Time_value Time_value == Year/Month/Day-Hour:Minute:Seconds Year == Integer [all 4 digits] Month == Integer [1 - 12] Day == Integer [1 - 31] Hour == Integer [0 - 23 ... e.g. 15 for 3pm] Minute == Integer [0 - 59] Seconds == Real [0.0 - 59.9999] Subject_ID == Alpha Log_version == v1 Time_zone == Number Generator_ID == generator=Alpha Browser_hardware == browser_hw=Alpha Browser_software == browser_sw=Alpha Tester_ID == tester=Alpha Procedure == procedure=Alpha Session_set_ID == sset=Alpha Ad_hoc_region == Ad_hoc_fields Newline Ad_hoc_fields == (Keyword=Value)* [Keyword must not match a defined keyword] Keyword == Label Value == Alpha Number == Signed_Integer | Signed_Real Log_block == Task_block | Questionnaire_block | Event_record | Note_record | Comment_record Note_record == note Begin_time Author Note_content Ad_hoc_region Author == subject | tester | unknown | Alpha Note_content == Alpha Comment_record == "--" Any_character* Newline [The 3rd character of the record (immediately following the initial "--") need not be blank.


Describes a usability testing session. We define a session as the interaction of a single subject with a single fully configured system under test during a continuous time interval. A switch of platform or subject is therefore considered to be a new session, by definition.
Contains information global to this session.
Begin_time, End_time
The times at which a session, or some other entity with duration, begins and ends.
Structured representation of a point in time. Seconds must be in fractional format even if the resolution is less than that. E.g. "45.0" rather than "45".
A string that uniquely identifies the person whose activity is being logged. This could be a label pointing to a file or some other data entry with a full demographic description.
Describes which version of this specification the file conforms to. For now, there's only one possibility, namely "v1".
Identify the time zone in which the time_values of the session are expressed. E.g. -5 for Eastern Standard Time. Subtracting the time zone (expressed in hours) from the time_values yields universal time. Real numbers are allowed because some zones are on the half-hour.
Identify the logging software that wrote this file. This may include or imply such information as which types of events the generator is capable of detecting and reporting.
Information about the client hardware on which the session took place. Such things as machine speed and screen characteristics can be captured here. This may be useful for comparison among sessions.
Identifies such information as the browser version and operating system.
This field identifies the person (normally a usability engineer) primarily responsible for setting up the test session.
This field describes or points to the procedure used to set up and perform the test session. Information such as how the subject was instructed, the general setting of the room, etc, may be entered here. Also, if certain kinds of events are selected for inclusion or exclusion (e.g. ignore pointer_moves, record key_presses), this would be an appropriate place to make note of that.
This allows several interacting sessions to be associated. E.g. if several subjects are testing collaborative software, their sessions could all be tagged with the same session_set_ID, to allow automated analysis of their interaction.
While there are no defined fields other than End_time, Log_end may also be used to capture summary data and information specific to the session, e.g.


Allows writers and readers of a logfile to convey information unanticipated by this specification. For instance, if the color of the room in which the session is held is deemed significant, the Log_header could legally contain: "room-color=yellow". Generic logfile readers/analyzers are expected to ignore these fields.
This record captures information typed in during the session by the subject or tester or some other Author. The idea is that test session manager software might provide a facility for observations, comments, complaints, or recommendations by interested parties if they encounter some unusual situation. This could be invoked at the initiative of the note's Author or prompted by the system. The Begin_time is the time at which the author started composing the note. If the subject is the Author, therefore, he/she was not engaged in the application task.
This record has no defined meaning and generally should be skipped by software that uses the logfile as input. It may be inserted and/or read by a human operator to clarify the meaning of nearby logfile records or other purposes.

Specification: Tasks


Task_block == Task_header Task_entry* Task_summary Task_header == taskhead Begin_time Task_type_ID website=Website_ID testdata=Testdata_ID Ad_hoc_region Task_type_ID == Alpha Website_ID == Alpha Testdata_ID == Alpha Task_entry == Event_record | Questionnaire_block | Note_record | Comment_record Task_summary == taskend End_time Task_type_ID Ad_hoc_region [Task_type_ID must match Task_type_ID from Task_header]


The FLUD file format is designed for task-oriented usability testing: the subject is given a task to perform (e.g. find at least three documents about Iowa, find out how much a Boeing 747 weighs) and then his/her performance is monitored. Undirected browsing can also be recorded within a single "dummy" task.
Holds information pertaining to an entire single task within the session.
Uniquely identifies the type of task that the subject is to perform. For instance, the task of discovering the weight of a 747 might be labeled as "find-weight-747". There might well be several instances of the same task type within a session if the subject is asked to perform the same task under varying circumstances. Also, this allows comparison of task performance across sessions.
Not necessarily an URL, although it may be - this identifies the whole site or sub-site being tested, not just a single page. Successful performance of the task may require the subject to visit several pages. Also, this might be used to identify which version of a website is being tested.
Identifies the underlying data file(s) or database with which the subject is interacting in this task. It may be the name of a file or directory.
Denotes completion of task (whether successfully accomplished or not). An application-savvy generator may well want to use ad hoc fields here to report summary metrics from the task, e.g. number_found=6.

Specification: Events


Event_record == event Event_header User_widget_effect Newline Event_header == Event_time Window_ID URL? Event_time == Time_value | Partial_time_value Partial_time_value == Hour:Minute:Seconds [inherits the most recently specified date - careful: need full Time_value for midnight rollover] Window_ID == Alpha URL == url=Alpha User_widget_effect == User_action? This_widget? System_effect* [at least one of these three must be present.] User_action == #U (Defined_user_action | Ad_hoc_user_action) Ad_hoc_fields Defined_user_action == Key_press_event | Key_release_event | Pointer_press_event | Pointer_release_event | Pointer_move_event | Six_DOF_event | Enter_widget_event | Leave_widget_event | Enter_window_event | Leave_window_event Key_press_event == keypress XY_location Key_ID Key_release_event == keyrelease XY_location Key_ID Key_ID == key=Key_data Key_data == Key_mod* (Key_character | Key_label) Key_mod == shift- | ctl- | meta- | alt- Key_label == f1 | f2 | ... | sp | vt | tab | ff | cr | ht | bs | esc | page_up | page_down | arrow_up | arrow_down | arrow_left | arrow_right | home | end | insert | delete | Plain_char Plain_char+ [Key_label must be at least 2 characters to distinguish it from Key_character. The space character must be represented as the label "sp", not as an actual space.] Pointer_press_event == pointerpress XY_location Button_ID Pointer_release_event== pointerrelease XY_location Button_ID Button_ID == usa-button=Button_data Button_data == Key_mod* Integer [start at 1: 3-usa-button mouse is labelled as 1,2,3, not 0,1,2] Pointer_move_event == pointermove XY_location Six_DOF_event == six_DOF XY_location? shift=Three_D_data rotate=Three_D_data Three_D_data == Signed_Real,Signed_Real,Signed_Real Enter_widget_event == enterwidget Leave_widget_event == leavewidget [Event_record must contain This_widget field if enter or leave widget is reported.] Enter_window_event == enterwindow Leave_window_event == leavewindow Ad_hoc_user_action == User_action_type XY_location? User_action_type == Label XY_location == screen_xy=XY_value | window_xy=XY_value | webpage_xy=XY_value This_widget == #W Widget_info Ad_hoc_fields Widget_info == Widget_ID Widget_type_value Widget_level? Widget_ready? Widget_ID == Alpha Widget_type_value == usa-button Bvalue? | radio Bvalue? | checkbox Bvalue? | textbox TXvalue? | menu Avalue? | slider Nvalue? | scrollbarH SCvalue? | scrollbarV SCvalue? | handle Bvalue? | link Bvalue? | Label Avalue? Bvalue == value=Boolean Avalue == value=Alpha Nvalue == value=Number SCvalue == value=Scroll_value TXvalue == value=Text_value Scroll_value == Real,Real Text_value == Quoted_string(:Cursor_position)? | :Cursor_position Cursor_position == XY_value Widget_level == level=(page | browser | window | system | Label) Widget_ready == ready=(focus | blur | hidden | displayed | Label) System_effect == (Other_widget | Window_state | Webpage_operation) Ad_hoc_fields Other_widget == #OW Widget_info Window_state == #WN Window_spec Window_op Window_spec == "*" | Window_ID Window_op == open Rectangle_position? | close | icon | de_icon Rectangle_position? | move Rectangle_position | resize Rectangle_position | raise | lower | focus | blur | Label Rectangle_position == up_left=XY_value low_right=XY_value Webpage_operation == #OP (Defined_web_op | Ad_hoc_web_op) Ad_hoc_web_op == Label Defined_web_op == print URL? | newpage Newpage_op Window_spec URL | page_locate Window_spec URL Page_loc_info Page_loc_info == horizontal=Scroll_value (vertical=Scroll_value)? | vertical=Scroll_value Newpage_op == request | loading | complete | Label

Summary of defined events


  • User_action
    • Key_press_event, Key_release_event
    • Pointer_press_event, Pointer_release_event
    • Pointer_move_event
    • Six_DOF_event
    • Enter_widget_event, Leave_widget_event
    • Enter_window_event, Leave_window_event
  • This_widget
    • usa-button
    • radio
    • checkbox
    • textbox
    • menu
    • slider
    • scrollbarH, scrollbarV
    • handle
    • link
  • System_effect
    • Other_widget [entries same as This_widget]
    • Window_state
      • open, close
      • icon, de_icon
      • move, resize
      • raise, lower
      • focus, blur
    • Webpage_operation
      • print
      • newpage
        • request
        • loading
        • complete
      • page_locate


Describes a single event. An event is considered to be nearly instantaneous and so only one time applies to it. More complex actions with a significant duration (such as drag-and-drop) are represented as a sequence of events. There are three kinds of substantive components of an event: User_action, This_widget and System_effects (see below). These are related causally; they are not merely co-temporal. An example would be a user clicking on a "close window" usa-button. The user_action is the mouse click, the widget is the labelled usa-button, and the effect is the actual closing of the window.

An event_record need not contain all three components. A component may be omitted because there is no information to report (e.g. no This_widget field because the user_action is not directed at a widget) or because the generator chooses not to report it. Moreover, a causally related user_action and system_effect may be reported within a single Event_record or in several. E.g. if the user clicks on a link, the resulting page may not show up for some time thereafter, and so its appearance may be reported in a later record as a separate event.

These fields apply by default to all the components of the event_record. The window and URL information may be overridden by more specific information within a component.
Events are considered to be instantaneous (zero duration), and therefore have a single time-stamp, not a begin and end time.
Inherits date information from most recent explicit Time_value in the preceding records of the file. Midnight rollover must be reported explicitly, i.e. "11:59:50.1" should be followed by something like "2000/05/17-00:00:22.3", not just "00:00:22.3". All time values within the file must be greater than or equal to the preceding value.
The Window_ID field in the event_header indicates where the user action is directed, where the widget is located, and (usually) where the effects take place. If a different window is affected, this is denoted in a field within System_effects. When representing user interaction with a webpage with multiple frames, it is recommended that the frame be identified as a subwindow through the use of an appropriate name, e.g. "win_237.frame_02".
The URL field likewise indicates which URL is the target of the user action and (by default) where the effects take place. The value of this field is a fully-qualified URL. If a webpage contains relative URLs, it is the responsibility of the generator to resolve these into absolute URLs before recording them in the logfile. The URL field is optional for two reasons: first, the user_action may not be directed to an URL, but rather to some other software component, such as a browser usa-button. Second, the logfile has an implicit window-to-URL mapping at any point, based on the newpage system effects, and so one can infer the URL, given the window.
A user_action is performed directly by the user and is associated with a particular input device, typically a mouse or a keyboard.
Key_press_event, Key_release_event
User presses or releases a key on a keyboard. XY_location is determined by the system pointer. Key_ID indicates which key was pressed/released.
Pointer_press_event, Pointer_release_event, Pointer_move_event
User presses or releases a usa-button on system pointer (e.g. mouse), or simply moves it.
User manipulates a device with six degrees of freedom (such as a spaceball). Such devices are often used in 3D applications to model rigid transformations (shift and rotate). XY_location is determined by the system pointer.
Enter_widget_event, Leave_widget_event
User moves system pointer into or out of a widget. The event_record must contain a this_widget component to identify which widget was affected.
Enter_window_event, Leave_window_event
User moves system pointer into or out of a window. The affected window is specified by the Window_ID in the Event_record header.
Location in pixels, where user_action is directed. Location may be relative to the entire screen, the window of the event_header, or the webpage of the event_header.
Describes the widget, if any, to which the user_action was targeted. Screen objects such as usa-buttons, textboxes, menus, and sliders are typical widgets. Note that while a user_action is always directed towards at most a single widget, several widgets could be affected as a result. E.g. clicking a single "Clear" usa-button may cause various textboxes, radiousa-buttons, and checkboxes to change state. Multiple effects may be represented in the Other_widget field of system_effects.
Uniquely identifies a widget. Two distinct window areas with the same function are considered to be distinct widgets. E.g. if there is a "return to index" usa-button at both the top and bottom of a webpage, these are distinct widgets with distinct names. It is recommended that:
  • The widget name map in a reasonable way to a visible label, when one exists. E.g. a "reload" usa-button could be named "win_01.reload".
  • Names of radiousa-button widgets reflect the related set to which they belong, e.g. "pizza_size.small", "pizza_size.medium", "pizza_size.large".
  • Names of checkbox widgets reflect the related set to which they belong, e.g. "pizza_topping.anchovy", "pizza_topping.pepperoni", "pizza_topping.mushroom".
The widget type determines what values and operations are available for that widget:
Buttons have no state - they simply initiate some action: e.g. do, calculate, search, submit, clear. A special case is a usa-button that opens a menu. Buttons take a Boolean value, where "yes" indicates the usa-button was pressed, and "no" that it was not.
Radiousa-buttons have a binary state and are used to indicate a "one of many" selection, e.g. pizza size: small, medium or large. Each radiousa-button toggles on and off; toggling on causes other radiousa-buttons in the related set to turn off. It takes a Boolean value, where "yes" indicates the toggle on and "no" is toggle off.
Checkboxes have a binary state and are used to indicate a many of many selection, e.g. pizza toppings: anchovies, pepperoni, mushroom. Each checkbox toggles on and off; toggling has no effect on other checkboxes in the related set. It takes a Boolean value, where "yes" indicates the toggle on and "no" is toggle off.
Textboxes accepts a textual entry, usually with editing allowed. The contents may consist of several lines. The state is the current text contents and location of text cursor. Textbox takes a Text_value value indicating current contents and/or text cursor position. The units of the Cursor_position field are interpreted as characters and lines, rather than pixels. If the cursor is in front of the first character of the first line, its position is 0,0. If in front of the 3rd character on the 7th line, its position is 2,6.
A menu allows selection one of many displayed choices, but the state not retained. It takes an Alpha value, indicating which selection was made. Although functionally somewhat similar to a set of radiousa-buttons, a menu is treated as a single widget.
Lets the user adjust some continuous one-dimensional numeric quantity (integer or real). Its state is the current numeric value. It takes a Number value.
scrollbarH, scrollbarV
This widget is a slider on the border of a window, used to adjust the position of a page within the window: scrollbarH for horizontal or scrollbarV for vertical. Its state value is the sub-page implicitly requested by the widget. Two numbers are needed to characterize Scroll_value, meaning: fraction of webpage cropped at top/left, and fraction cropped at bottom/right. E.g. if lines 23 through 65 of a 100-line document are requested, the vertical crop values would be 0.22 (top) and 0.35 (bottom).
A handle is used for dragging to adjust window geometry, e.g. for moving or re-sizing a window. There is no state. A handle takes a Boolean value, where "yes" indicates the handle is being actively used and "no" that it is not.
A link is an active region (text or image) of a webpage (but not a conventional widget) on which clicking causes an attempt to display a new webpage or new location within the current webpage. The new entity may show up in the same or a new window. Link takes a Boolean value, where "yes" indicates the link was activated and "no" that it was not. The Widget_ID identifies the region of the page used as a link.
The component directly containing the widget at which the user action is targeted.
The widget is part of a displayed webpage, e.g. a checkbox.
The widget is one of the standard browser controls, e.g. the back usa-button or a scroll bar to adjust page position.
The widget is one of the standard window controls, e.g. the resize handle.
The widget is one of the operating system controls, e.g. a usa-button to launch a new process.
Describes the visibility and/or availability of the widget to accept user input:
The widget is ready to accept user input, e.g. an active textbox that gets input from the keyboard. Focus implies displayed.
The widget is not ready to accept user input, e.g. an inactive textbox.
The widget has become hidden, e.g. when a pull-down menu is collapsed.
The widget has become visible, e.g. when a user_action causes a menu to be displayed.
System_effect is used to describe how the state of the system (as seen by the user) changes as a result of the user_action, other than immediate changes in the state of the widget directly targeted.
The components of other_widget have the same interpretation as in This_widget, except that the other_widget changed state as an indirect effect of a user_action. E.g. if the user presses a "Clear" usa-button, that usa-button is directly affected, but other widgets may change state as a result - textboxes cleared to the null string, checkboxes set to "off", etc. These other changes could be packaged up into one event_record along with the targeted widget, they could be represented in a distinct event_record, or they could each have their own event_record. In the latter two cases, however, the causal connection between the original user_action and the resultant widget state changes would be more difficult to reconstruct.
Reports changes in the state of one of the windows of the web application.
A window_spec of "*" means that the Window_ID in the event_header is the one in which this state change has occurred. An explicit Window_ID in the Window_spec overrides the Window_ID in the event_header.
The defined window operations are as follows. When rectangle_position is given, it indicates the location of the window in pixel coordinates relative to the full screen.
A new window appears on the screen.
An existing window is deleted from the screen.
The window is iconified - represented as a small region and temporarily de-activated.
The window is de-iconified - restored to full size from an iconified state.
The window's position on the screen changes.
The window's size and possibly shape on the screen changes.
The window is raised so as to be fully visible and therefore may obscure other windows.
The window is lowered so as to be potentially obscured (partially or fully) by other windows.
The window is ready to accept user input, e.g. from the keyboard.
The window is will not accept certain user input, e.g. from the keyboard.
Webpage operations include loading of webpages but also any application-specific operations that can reasonably be detected and represented. A description of the defined webpage operations (defined_web_op) follows:
A webpage is printed out. The URL to be printed out is taken from (in order of preference), an explicit URL field, the URL of the event_header, or the URL associated with the window in the event_header.
Newpage encompasses events surrounding the retrieval and display of a new web page. The URL is that of the new page. Note that jumping to an internal link normally results in a page_locate effect (see below), not a newpage. The window_spec indicates in which window the URL will be displayed. The defined newpage operations include:
The user has issued a request for a webpage. The webpage may or may not exist and may or may not be successfully retrieved.
The webpage has been found and its retrieval and display have begun.
The webpage has been found and its retrieval and display have been completed.
A webpage (specified by the URL field) changes location within a window (specified by Window_spec), perhaps as a result of page scrolling, window re-sizing, or jumping to an internal link. The horizontal and vertical parameters describe the precentage of the page that is cropped at the left/top and right/bottom.

Specification: Questionnaires


Questionnaire_block == Q_header Q_entry* Q_end Q_header == qhead Begin_time Questionnaire_ID Ad_hoc_region Questionnaire_ID == Alpha Q_entry == Q_record | Comment_record Q_record == qrec Question_ID Response Ad_hoc_region Question_ID == Alpha Response == Alpha Q_end == qend End_time Ad_hoc_region


This captures the results of a portion of the session wherein the subject responds to a questionnaire set up by the tester. The difference between a questionnaire and a task is that a questionnaire requests information directly from the subject (e.g. "how old are you?", "do you think the graphics are helpful or annoying?"), whereas a task is usually meant to simulate the intended usage of the website and the subject is monitored to find out such things as whether most people use the website effectively. Also, only the results of the questionnaire are reported, not the process by which they were answered (e.g. timing of the responses is not reported).
Report with which questionnaire the subject is interacting, and when the interaction started.
Each Q_record captures the response to a single question of the questionnaire. The intention is that the Question_ID simply identifies which question is being answered, rather than repeating the entire question verbatim. All questions answered during the time span of the questionnaire must be reported. Only the final responses of the user should be reported (e.g. if the user first clicks "green", then "red" in response to a question, only the latter should be reported). If the user does not give a response to a question, this may be reported either by simply omitting the Q_record for that question, or by a Response of "" (an empty Quoted_string).
Report when the user's interaction with the questionnaire ended.

Specification: Low-level constructs


Alpha == Label | Quoted_string Label == Plain_char+ Plain_char == Letter | Digit | - | _ | . | : XY_value == Signed_Integer,Signed_Integer Signed_Real == Optional_sign Real Signed_Integer == Optional_sign Integer [no spaces within signed numbers] Real == Integer . Integer? Integer == Digit+ Optional_sign == ("+" | "-")? Boolean == yes | no Letter == A | B | C | ... | Z | a | b | c | ... | z | Digit == 0 | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9


Label (%s)
An unquoted alphabetic string. May be used as a self-explanatory literal or as a pointer to some fuller description. E.g. a Subject_ID with a value of JoeJones could be treated as a simple designator of a person or used as a filename, with the file containing a fuller description of the person (birth date, sex, SSN, etc.).
An ordered pair of integers used to locate an interaction within a window. The first number (X) specifies a horizontal location, and the second (Y), a vertical location.
Real (%f)
A real number, fixed-point format (must have decimal point).
Integer (%d)
A non-negative integer.

Context-sensitive grammar rules.

  • All Time_values and Partial_time_values within the file must be in ascending order, i.e. If time X textually precedes time Y within the file, then the time designated by X must be no later than that designated by Y.
  • The Year field is interpreted as a complete value - no implicit centuries. E.g. the year 1998 is represented by "1998" or even "001998", not simply "98".
  • All Time_values and Partial_time_values must designate actual times: Month between 1 and 12, Day between 1 and number of days in the month, Hour between 0 and 23, Minute between 0 and 59, 0 <= Seconds < 60.
  • Keywords in an Ad_hoc_field must not match any defined keywords.
  • The Task_type_IDs of a Task_header and Task_summary within the same Task_block must be the same.

Explanation of unresolved non-terminal symbols

A string of characters enclosed in double quotes ("). An Alpha entry must be quoted if it contains non-plain characters. The backslash conventions of C are used to represent "funny" characters within the string; in particular \" stands for a double quote, \n for a newline character, and \\ stands for a true backslash. A quoted_string could be used as a pointer or filename, but also as a literal description.
Any_character (%c)
Any character other than newline.
Key_character (%c)
Any non-whitespace (printable) keyboard character.
A newline character, signifying end of a record.

5. Example

Logfile records tend to be too long to fit on a conventional single printed line, so these records have been broken up for display purposes only, using a trailing backslash to indicate continuation. True logfile records may not be broken up in this way.

loghead 2000/01/18-13:33:44.22 subject=jcugini version=v1 time_zone=-5 \ generator=WebVIP browser_hw=SGI-Indigo-2 \ browser_sw="netscape-v4.2 for IRIX6.5" taskhead 2000/01/18-13:33:46.12 task01 website=VVR-home testdata=default.dat -- here we see a page being "spontaneously" loaded - at least, -- there is no record of a user request event 2000/01/18-13:33:46.44 win_01 \ #OP newpage loading * url="" event 2000/01/18-13:33:46.44 win_01 \ #OP newpage complete * url="" -- in the next two records, the user grabs the resizing handle on -- the window and resizes it; only the initial and final state are shown. event 2000/01/18-13:33:48.22 win_01 \ #U pointerpress screen_xy=22,33 usa-button=1 \ #W win_resizer handle value=yes level=window ready=focus event 2000/01/18-13:33:49.9 win_01 \ #U pointerrelease screen_xy=212,343 usa-button=1 \ #W win_resizer handle value=yes level=window ready=focus \ #WN * resize up_left=11,22 low_right=345,567 -- Random keypress, with no effect event 2000/01/18-13:33:54.22 win_01 url="" \ #U keypress webpage_xy=234,432 key=f3 -- a questionnaire block qhead 2000/01/18-13:33:55.11 Questionnaire_22 qrec Q_006 "about once a week" qrec Q_007 7.233 qend 2000/01/18-13:33:56.2 -- user clicks on an active image to request a newpage event 2000/01/18-13:33:56.3 win_01 url="" \ #U pointerpress webpage_xy=4,5 usa-button=shift-2 \ #W "details.jpeg" link value=yes level=page \ #OP newpage request * url="" event 2000/01/18-13:33:56.8 win_01 url="" \ #U pointerrelease webpage_xy=4,5 usa-button=shift-2 \ #W "details.jpeg" link -- user slides mouse off the old window event 2000/01/18-13:33:58.1 win_01 \ #U leavewindow -- new window opens and new page appears as requested event 2000/01/18-13:33:58.6 win_02 \ #WN * open up_left=20,10 low_right=520,810 event 2000/01/18-13:34:01.1 win_02 \ #OP newpage loading * url="" event 2000/01/18-13:34:02.2 win_02 \ #U pointermove webpage_xy=45,67 event 2000/01/18-13:34:03.1 win_02 \ #OP newpage complete * url="" \ #OP page_locate win_03 url=""\ horizontal=0.0,0.0 vertical=0.0,0.37 -- user clicks on a radio usa-button, specifying yogurt event 2000/01/18-13:34:03.6 win_02 \ url="" \ #W "dessert.yogurt" radio value=yes -- what was he thinking - opts for mango instead - notice state -- change in original widget event 2000/01/18-13:34:03.7 win_02 \ url="" \ #W "" radio value=yes \ #OW "dessert.yogurt" radio value=no -- user types "glorp" into a textbox event 2000/01/18-13:34:04.1 win_02 \ url="" \ #U enterwidget \ #W "comment.txt" textbox value="":0,0 level=page ready=focus event 2000/01/18-13:34:04.2 win_02 \ url="" \ #U keypress webpage_xy=2,3 key=g \ #W "comment.txt" textbox value="g":1,0 event 2000/01/18-13:34:04.3 win_02 \ url="" \ #U keypress webpage_xy=2,3 key=l \ #W "comment.txt" textbox value="gl":2,0 event 2000/01/18-13:34:04.4 win_02 \ url="" \ #U keypress webpage_xy=2,3 key=o \ #W "comment.txt" textbox value="glo":3,0 event 2000/01/18-13:34:04.5 win_02 \ url="" \ #U keypress webpage_xy=2,3 key=r \ #W "comment.txt" textbox value="glor":4,0 event 2000/01/18-13:34:04.6 win_02 \ url="" \ #U keypress webpage_xy=2,3 key=p \ #W "comment.txt" textbox value="glorp":5,0 event 2000/01/18-13:34:04.9 win_02 \ url="" \ #U leavewidget \ #W "comment.txt" textbox value="glorp":5,0 level=page ready=blur -- end of task taskend 2000/01/18-13:34:45.00 task01 num_found=22 time_taken=26.23 -- questionnaire outside of task qhead 2000/01/18-13:34:48.11 Questionnaire_22 qrec Q_001 yes qrec Q_002 37 qrec Q_003 b qrec Q_011 fewer qrec Q_012 "yes, but with more fish" qend 2000/01/18-13:38:11.2 taskhead 2000/01/18-13:40:00.01 task-glorp website=VVR-home \ testdata=default.dat event 2000/01/18-13:40:02.2 win_01 \ #OP newpage loading * url="/aa" event 2000/01/18-13:40:04.2 win_01 \ #OP newpage complete * url="/aa" event 2000/01/18-13:40:07.6 win_01 \ #OP newpage request * url="/bb" event 2000/01/18-13:40:11.2 win_01 \ #OP newpage complete * url="/bb" event 2000/01/18-13:40:22.3 win_01 \ #OP newpage complete * url="/cc" event 2000/01/18-13:40:26.5 win_01 \ #OP newpage complete * url="/cc" event 2000/01/18-13:40:29.9 win_01 \ #OP newpage loading * url="/cc" event 2000/01/18-13:40:44.4 win_01 \ #OP newpage request * url="/ff" event 2000/01/18-13:40:55.1 win_01 \ #OP newpage request * url="/dd" note 2000/01/18-13:40:56.2 subject This was a stupid test... taskend 2000/01/18-13:41:02.2 task-glorp num_found=22 time_taken=26.23 note 2000/01/18-13:43:56.2 tester No it wasn't logend 2000/01/18-13:50:00.0 status=completed num-tasks=2

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Created September 29, 2016, Updated October 3, 2023