using graphs to present data constructing graphs and interpreting data
TRANSCRIPT
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 Chart Level 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
0
100
200
300
400
500
600
Nu
mb
er
of
ch
ild
ren
(y
axi
s)
Age (x axis)
Number of Children with Incomes Under the Poverty Line
Under 5
6 to 12
13 to 18
Pie Chart
Ethnicity of Survey Respondents
7% 3%
14%
29%
37%
10%
African American
American Indian
Asian
Caucasian
Latino
Other
Percents for Pie Chart
African American
American Indian
Asian Caucasian Latino Other Total
5 2 10 20 25 8 70
7.14% 2.86% 14.29% 28.57% 35.71% 11.43% 100.00%
Histogram: Ages of MSW students responding to exit survey
Graph
AGE
60.055.050.045.040.035.030.025.0
20
10
0
Std. Dev = 10.18
Mean = 34.0
N = 56.00
Line Chart
Sales Figures by Quarter
0
20
40
60
80
100
1st Qtr 2nd Qtr 3rd Qtr 4th Qtr
Quarters
Sal
es i
n M
illi
on
s
Techniques for Making Comparisons: Histogram
0102030405060708090
Sales in Dollars
1st Qtr 2nd Qtr 3rd Qtr 4th Qtr
Quarters
Sales by Region in Each Quarer
East
West
North
South
Techniques for Making Comparisons: Line Chart
Sales Figures by Region
0
20
40
60
80
100
1st Qtr 2nd Qtr 3rd Qtr 4th Qtr
Quarters
Sal
es i
n D
oll
ars
East
West
North
South
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 –
ABA Design
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10
20
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40
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60
70
1 2 3 4 5 6 7 8 9 10 11 12 13 14
Baseline Intervention Baseline
Lo
w S
elf-
este
em
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.