640 likes | 708 Views
Learn survey data terminology, table design, validity concepts, and SPSS Output Viewer usage for accurate data analysis and reporting. Discover methods for handling missing data, precision, and formatting tables and charts efficiently.
E N D
GAP Toolkit 5Training in basic drug abuse data management and analysis Table manners Training session 10
Objectives • Define the common terminology used to evaluate survey data • Establish the information that should be reported with the data, whether the data take the form of a table, a graph or numerical summaries • Introduce the Output Viewer in SPSS • Describe formatting charts and tables
Conflicting aims • A table has two purposes: • To put across a point • To allow the reader to verify our claims with reference to the data • “These aims are not always the same and getting the balance right is as much an art as a science.” (C. Marsh, Exploring Data: An Introduction to Data Analysis for Social Scientists (Cambridge, Polity Press, 1988)).
Survey terminology • Reliability • Validity: • Internal • External
Reliability • A tool of measurement displays reliability if it records the same result in repeated applications under identical conditions • For example: • I weigh myself on my bathroom scales on Monday and weigh 100 kg • I weigh myself on my bathroom scales on Tuesday and weigh 72 kg • This would be nice, but is unlikely: the scales are probably unreliable
Validity • Validity takes various meanings in survey design • Internal validity is the ability of the measure (the question or observation) to adequately represent the underlying concept of interest
External validity • External validity refers to the ability to abstract generalizations from the results: • Are the data from a sample? • If “yes”, is that sample a reasonable representation of the population? • If so, can the results be generalized to the population?
Table design • Clarity: • Structure • Message • Completeness
Titles • Who/What? • When? • Where?
Source • It is essential that the source of the data is presented regardless of what form the statistics take • The source of the data helps establish the authority of the data
Variables • Definitions • Units
Percentages • If a variable is measured in percentages, be certain it is clear what it is a percentage of: • Rows • Columns • Totals • Ensure that the original numbers can be calculated by reporting the sample size (the size of the denominator in the calculation of the percentage)
Method • Sample statistics are frequently used to make general statements about the population • If the statistics are drawn from a sample, state the method of sampling • The method determines the external validity of the results
Missing data • Always report the number of missing observations in your data set • A large amount of missing data brings into question the external validity of a survey: • Those who agreed to answer and those who refused may well have different characteristics
Precision • Avoid reporting data to unjustifiable levels of precision • Round results to the level of precision of the original data
Output Viewer • The third main window in SPSS • Used to edit and format the results of any statistical analysis • Generates output files with the suffix .spo
Exercise: Session 8: Output • Retrieve the output file “Session 8 freq.spo” saved in session 8
Output Table of contents
Left-hand panel • Use the left-hand panel to manage the output • Clicking on a heading selects that part of the output • Clicking on the – sign to the left of a heading hides or collapses the output • Clicking on the + to the left of a heading displays or expands the output
Right-hand panel • Select a single piece of output by pointing and clicking once • Select multiple pieces of output by holding down the Ctrl key while clicking more than once • Format output by pointing and double-clicking
Copying tables to Word • Select the output in the left-hand panel or in the Viewer • Edit/Copy • Move to Word • Edit/Paste Special: • Formatted Text • Unformatted Text • Picture
Copying charts to Word • Select the output in the left-hand panel or in the Viewer • Edit/Copy • Move to Word • Edit/Paste
Exercise: copying to Word • Copy the frequency table for Education to a Word document as: • Formatted text • Unformatted text • Picture • Copy the bar chart of Education to the same Word document as a picture
Formatting tables • Double click to enter formatting mode • A new border appears around the output with short diagonal lines at a 45-degree angle • The menu bar now contains formatting options
Editing the table • Edit any component of the table by double-clicking that particular part of the table • A box will appear in which the table can be edited
Race of clients: treatment centres in the Cape region of South Africa January-June 2001
Insert • Insert/Title • Insert/Caption • Insert/Footnote
Race of clients: treatment centres in the Cape region of South Africa January-June 2001 Source: The data were collected from the treatment centres as part of the South African Drug Information System.
Race of clients: treatment centres in the Cape region of South Africa January-June 2001 a Source: The data were collected from the treatment centres as part of the South African Drug Information System. a Note that the small number of Asian clients raises issues of the generalizability of the results pertaining to the Asian community.
Format • Format/Table Properties • Format/TableLooks
Race of clients: treatment centres in the Cape region of South Africa January-June 2001 Source: The data were collected from the treatment centres as part of the South African Drug Information System. a Note that the small number of Asian clients raises issues of the generalizability of the results pertaining to the Asian community.
Formatting charts • Double-click a chart in the Output Viewer to open the chart in the Chart Editor • To edit or format the chart: • Point at the part to be edited and double-clickOR • Use the menu bar options