Frequency Map

From BEARWiki
Jump to: navigation, search

Frequency Maps display frequency distributions of students' proficiency levels on the selected instrument (item set). For this example, we use the SEPUP Demo project (Load with Help - Demo Projects - SEPUP Demo).

1. Select Reports – Group Reports - Frequency Map. Dialog windows for entering display options will be provided.

Freq dialog1.png Freq dialog2.png
Figure 1. Frequency Map Options.


Table 1. Display options for Frequency Maps.
Option Description
Title The report title you provide will appear at the top of the report below the Project Title (set in Report Options) and also as the title of the window when the report is displayed.
File name Location where PNG images of the graph will be stored. For multidimensional models, system will automatically append "_varname" to each filename.
Item Set Browse... to the Item Set (Assessment) that you want included. If you want to see all of the items, select the “base” Item Set.
Performance Axis Label Enter the label you wish to appear along the latent trait axis (typically the y-axis).
Display Scores Select Yes if you want score values (e.g., logits; can be set in Report Options) to be displayed along the Performance Axis; select No if you do not want score values displayed. Criterion Zone labels are always displayed along the right margin if they have been defined (define them in the Editing Criterion Zones section)
Show Student Counts Select Yes if you want frequencies displayed; select No if you want percentages displayed.
Show Estimate Type Select Yes to see EAP, MLE, DPV in the heading; select No to omit the estimation type from the heading.
X-Axis Location Select Top to have the x-axis labels display across the top of the graph; select Bottom to have the labels appear at the bottom of the graph.
Displayed Range: Max & Min Shows the maximum and minimum scores that are applied to the Performance Level axis (although they may not be displayed). This information lets the user know how to select relevant bin widths to collect frequencies. If a user-defined scale has not been provided (e.g., in Report Options), then a logit scale will be used.
Bin width Users can select narrower or wider bin widths for aggregating proficiency estimates.
Background Color Use the adjacent Change Color button to change the background color for the map.
Cut-Point Color Use the adjacent Change Color button to change the color of the alternating horizontal Criterion Zones for the map.
Histogram Bar Color Use the adjacent Change Color button to change the color of the histogram bars.

As shown in Figure 2 below, the x-axis of the Frequency Map (with labels along the top margin) shows the scale for the frequencies of students, while the y-axis shows the proficiency levels (as logit values along the left edge). If Criterion Zones (Performance Levels) are defined, as they are in this example, the graph is subdivided into logit ranges associated with each Criterion Zone.

A map is generated for each variable in the model; select a variable to view by clicking on one of the tabs at the top of the map (in this example, either DCI or ET). In Figure 2 the DCI tab is currently selected, and in Figure 3 the ET variable is selected. The frequencies that are plotted are the counts of students who provided valid responses on items that were associated with each variable.

Figure 2. Frequency Map for the DCI variable.

The data in Figure 2 show that when students completed the first item set, comprised of activities 1 through 12, approximately 85% were performing at the Incomplete performance level in the area of Designing and Conducting Investigtions (DCI). In the SEPUP curriculum, this means that they are providing responses that are mostly correct, but missing one or two key features. Approximately 15% were providing responses that were completely correct. To obtain a more precise calculation of the percentages of students in each performance level, and a list of students in each, use the Ability Estimates by Level report.

Figure 3. Frequency Map for the ET variable.

In Figure 3 we see that all students were performing in the Incomplete performance level on items that assessed the way they Use Evidence and Make Tradeoffs (ET).

This is valuable information teachers can use to develop specific strategies to help students improve their performance. Rather than simply having traditional test information such as counts of students by percentage category (e.g., those who earned 90% or higher, those who earned 80% - 89%, etc.), teachers have more detailed information as to the specific skills and abilities that can be targeted. In addition to identifying the skills and abilities to focus on, teachers can see the level of work that students are producing to help them understand qualitative differences in performance rather than simply percentage point spreads.

2. Resize or change the shape of the map by dragging the corners of the map window, or the window edges. Some actions will crop the window, but dragging back will restore the window contents.

3. To print the map, select File – Print Selected Chart. This will print the map for the currently displayed variable. Use the tabs at the top of the map to select another variable, and then select File – Print Selected Chart again to print that map. This will print a full-size map. To control the size of the printed map, you may prefer to save it as a JPG or PNG file and then import it into a Word document (see the next step). You can then modify the size directly.

4. By default, the map is saved to the location you indicated in the Filename entry on the dialog window. To save the map to another location or in another format, select File – Save as JPG or Save as PNG, as shown in Figure 4. This will automatically save a graphical file for each variable. For example, entering a filename of “Freqmap” generates the files Freqmap_DCI.png and Freqmap_ET.png.
Figure 4. Menu for graphical reports in ConstructMap.

5. Close the map by clicking the Close button at the bottom of the window (or Close the window, or use the File – Exit option from the map menu).

Links