International Corpus of English

Using VOICE-Online

6 Filters

This section offers information on how the filter function can be accessed and on how filters can be selected, combined and disabled again.

The filter function allows 'filtering' the corpus, i.e. selecting specific corpus texts for searches. If the filter function is activated, i.e. one or more filters are selected, subsequent searches are limited to the corpus texts that have been selected, i.e. the searches are carried out only in these texts. If no filter is active (which is the default setting), searches are carried out on the entire corpus, i.e. all 151 corpus texts.

The two classes according to which texts can be selected via the filter function are domain and spet (speech event type).

6.1 Accessing the filter function

The filter function can be accessed by clicking on the bar labelled Filter at the bottom of the application area. When you click on this bar (Filter), it slides to the top of the application area and reveals the default caption Corpus currently not filtered. Click here to add filter if no filters have been selected beforehand.
Screenshot of application area if
			  no filters have been selected
Accessing the filter function

6.2 Selecting a filter

When clicking on the caption Corpus currently not filtered. Click here to add filter in the application area, a pop-up window for selecting filters appears in the content area.
Screenshot of filter pop-up
The filter pop-up for selecting a filter

A filter can be selected by clicking on one of the two filter options, i.e. domain or spet, and dragging the filter option into the grey box below (via the drag-and-drop function of the mouse).

The caption in the grey box now displays the selected filter class (e.g. domain). A drop-down menu lists the categories of this filter class (e.g. for domain: ED, LE, PB, PO, PR). Selecting a category from this list (e.g. PO) means selecting all the texts in this category (e.g. all texts in the domain 'Professional Organizational').
Screenshot of filter pop-up and domain PO chosen
Example: selecting all texts of domain PO
Subsequent searches are carried out only in the corpus texts in this domain.

6.3 Selecting a negative filter: excluding texts

The operation of selecting texts from a specific filter category can also be reversed, i.e. texts from the selected category (e.g. domain PO) can be excluded from corpus searches. This is done by clicking on the exclamation mark located at the left-hand side of the grey box. The exclamation mark as well as the caption in the grey box (e.g. domain) are indicated in red if the negative selection is activated. This means that the search engine now searches everything BUT the selected filter category.
Screenshot of filter pop-up and
			  domain PO chosen (negative)
Selecting a negative filter
Clicking on the exclamation mark again revokes the negation and turns the filter category into a positive selection again.

6.4 Viewing the current filter selection

The filter which is currently selected is represented in writing in the application area (e.g. domain(PO) or not domain(PO)).
Screenshot of filter pop-up and
			  domain PO chosen (note in application area)
The current filter selection
If the filter selection is adapted, the new selection is immediately shown in the application area. Once the filter selection has been completed, the pop-up window Edit Corpus Filter can be closed by clicking on the X-symbol. The filter remains active also after the pop-up has been closed (until the filter is removed again via the pop-up menu). The pop-up Edit Corpus Filter can be accessed and modified again by clicking on the current filter selection in the application area.
The current filter selection is also mirrored in the list of speech events in the corpus tree. Clicking on the bar Corpus Tree hides the information on selected filters and reveals the corpus tree. Here, the corpus texts which are selected via the current filter selection are represented in italics and flagged with a small filter symbol next to the event ID. Searches are carried out only in these texts.
Screenshot of filter selection in
			  corpus tree
The filter selection mirrored in the corpus tree

6.5 Combining filters

The filter function also offers the option of combining several filters which select (or exclude) different filter categories. Filters can be combined via the operators in the Edit Corpus Filter pop-up which are explained in the following.

6.5.1 Adding filters

A new filter can be added by clicking on the plus-symbol in the bottom left-hand corner of the pop-up box. Another grey box with the caption drop filter here appears for which a new filter category can be selected (see description for selecting filters above).
Screenshot of pop-up with 2nd filter
Adding a filter

6.5.2 Filter relationships: and/or operators

Two filter categories can relate to each other in two ways, which are represented by the and/or operators in the pop-up window.
Screenshot of operators
The and/or operators
Operator Description Example selects
and Both filter categories (i.e. conditions) need to be fulfilled by a text in order for the text to be selected for the search. domain PO AND spet wgd all texts in the Professional Organizational domain (PO) which are also working group discussions (wgd).
or One of the filter categories (i.e. conditions) needs to be fulfilled by a text in order for the text to be selected for the search. domain ED OR domain LE all texts from the Educational domain (ED) and from the Leisure domain (LE).

In its default setting, the and relationship is activated whenever a new filter is added. The and is indicated in black letters, while the or is represented in grey letters. The relationship can be changed by clicking on or, which is then indicated in black letters. Filter combinations that yield no matching texts

Obviously, some filter combinations will result in no matching texts. For example, a text cannot fulfill both the condition domain ED AND the condition domain LE as each text in VOICE is only part of one domain. Similarly, not all speech event types are represented in all domains in VOICE. For example, while selecting the filter categories domain PO AND spet mtg produces matching texts, the selection domain PO AND spet sed produces no matching texts, as there are no seminar discussions in the Professional Organizational domain in VOICE.

Whenever a filter combination produces no matching texts, this is indicated in the application area with the caption no matching texts for this selection. The filter selection then needs to be changed in order to find matching texts and render search results.
Screenshot of non-existent combination of filters
Filter combination that yields no matching texts A note of caution: nonsense combinations

The filter function is designed to be very flexible and powerful and allows all possible combinations of filter categories and operators. However, this means that using inappropriate filter combinations may result in no matches, and that some 'nonsense' combinations of filters are also possible.

An example: The filter combination not domain PO OR domain ED selects all texts except those in the PO domain. The second filter category (domain ED) is superfluous as the texts from the ED domain are already selected through the not domain PO filter category.

The responsibility of checking whether the combined filter categories produce a meaningful selection of texts rests with the corpus user.

6.5.3 Introducing filter hierarchies

Combinations of different filter categories can also be put into a hierarchical order. A filter category can be shifted to a higher hierarchical level by clicking on the grey double arrow located at the right side of the grey filter box.
Screenshot of introducing a filter hierarchy
Introducing a new filter hierarchy
Introducing such a hierarchy of filters allows the two different filter relationships (i.e. and/or) to be combined at different levels.
An example:
Screenshot of example of filter hierarchies
Example of filter hierarchy
The filter combination in the example above selects all texts from the ED domain and then further specifies that the texts also need to be either conversations (con) or seminar discussions (sed). Or, in a more formulaic representation: domain ED AND (spet con OR spet sed).

Clicking on the plus-symbol adds a filter at the current hierarchical level. Clicking on the minus-symbol removes the filter or shifts it back to the main level of hierarchy.

6.6 Removing filters

Filter categories can be removed by clicking on the minus-symbol located at the right side of the grey box. To disable the filter function, i.e. to cancel all limitations for searches, remove all grey boxes (by clicking on the minus-symbol) until the caption Corpus currently not filtered. Click here to add filter reappears in the application area. Close the pop-up window Edit Corpus Filter by clicking on the X-symbol. All filters have been removed and corpus searches now include all corpus texts.