Using graphs to present data Constructing graphs and interpreting data

Types of graphs commonly used in social work Bar charts Pie charts Histograms Line charts Charts for single system designs

You must use graphs that are appropriate to the level of measurement associated with the variable you are measuring Type of ChartLevel of Measurement Bar Chart Nominal; must be organized into categories Pie Chart Nominal, ordinal, interval, or ratio. However, it is not practical to use a pie chart when there are more than five or six possible values for a variable. Histogram Ordinal, interval, or ratio level data. Most often used with ratio or interval level data Line Chart/Frequency Polygram Interval and ratio data Single System Design Interval and ratio data

Bar Chart: Number of children with income under the poverty line

Pie Chart

Percents for Pie Chart African American American Indian AsianCaucasianLatinoOtherTotal %2.86%14.29%28.57%35.71%11.43%100.00%

Histogram: Ages of MSW students responding to exit survey Graph

Line Chart

Techniques for Making Comparisons: Histogram

Techniques for Making Comparisons: Line Chart

Single System Designs Used by practitioners to measure whether intervention is effective. Not a formal evaluation of worker performance. Comparisons are made by comparing baseline measures to intervention phase. Measures used are usually ratio: standardized scores or counting behaviors. Behavioral counts are usually self-reports Sometimes comparisons are made across clients, types of interventions, or types of behaviors

Single –system Design Graph –

Single System Designs include At least two phases, baseline and intervention. (AB design) Baseline is a period when clients do not receive an intervention. Intervention is when treatment is offered. The reason this is done is because things may be happening in the client’s life that affects the target behavior – you want to control for these effects by alternating no treatment with treatment – you can see if patterns are similar during both phases. Intervention is successful if there are changes in the trend line (up or down) after the intervention starts

Other types of designs ABA (baseline, intervention, baseline. ABC (baseline, Intervention #1, Intervention #2, etc.) Multisystems designs – targets two or more behaviors in the same client or two or more clients with the same problems and target behavior or attribute. Baseline for client number two is extended until after the intervention has started for client #1 in order to further control for the effects of the surrounding environment.

Issues with Single System Designs A variety of factors can influence the success or failure of the intervention – the agency, the worker, client-worker interaction, the client’s home or work environment – what happens in the client’s community or the country. You can’t generalize findings from one single system design to other clients, workers or settings.