SPSS is a widely used program for statistical analysis in social science. It is also used by market researchers, health researchers, survey companies, government, education researchers, marketing organizations, data miners, and others. The original SPSS manual (Nie, Bent & Hull, 1970) has been described as one of “sociology’s most influential books” for allowing ordinary researchers to do their own statistical analysis. In addition to statistical analysis, data management (case selection, file reshaping, creating derived data) and data documentation (a metadata dictionary is stored in the datafile) are features of the base software.
SPSS custom dialogs are extensions of SPSS’ point-click menu, officially known as the GUI (“graphical user interface”). SPSS Custom Dialogs in Menu Custom dialogs are kept in files with the .spd file extension. After installing a custom dialog file, it will appear in the menu just like an SPSS’ built-in command. The difference, however, is […]
Summary Creating dummy variables for several categorical variables by basic syntax is usually not hard. However, applying proper variable labels to the newly created dummy variables requires quite a bit of effort. The tool presented in this tutorial will take care of this -and some other issues- more easily. SPSS Dummy Variables Tool SPSS Create Dummy Variables Tool Instructions […]
Dummy coding a variable means representing each of its values by a separate dichotomous variable. These so-called dummy variables contain only ones and zeroes (and sometimes missing values). The figure below shows how the variable “pet” from favorite_pets.sav has been dummy coded as pet_d1 through pet_d4. Dummy Variables in SPSS Note that, for example, pet_d2 represents the value 2 on […]
Summary SPSS CORRELATIONS generates tables with Pearson correlations and their underlying N’s and p-values.* This tutorial quickly walks through its main options, using freelancers.sav for demonstrational purposes. User Missing Values Before running any correlations, we’ll first specify all values of one million dollars or more as user missing values for income_2010 through income_2014.* We’ll do so by running the following line […]
A magazine wants to improve their customer satisfaction. They surveyed some readers on their overall satisfaction as well as satisfaction with some quality aspects. Their basic question is“which aspects have most impact on customer satisfaction? ”We’ll try to answer this question with regression analysis. Overall satisfaction is our dependent variable (or criterion) and the quality […]
A magazine publisher surveyed readers on their overall satisfaction and a number of quality aspects. Their data can be downloaded from magazine.sav. Now, when working with real world data, the first thing you want to do are some basic data checks. This tutorial walks you through. The actual regression analysis on the prepared data is covered in the next […]
Among the very best SPSS practices is running histograms over your metric variables. Doing so is a super fast way to detect problems such as extreme values and gain a lot of insight into your data. This tutorial quickly walks you through using bank_clean.sav, part of which is shown below. Option 1: FREQUENCIES without Frequency Tables If you’re running […]
Introduction In SPSS we sometimes find ordinal variables where lower values indicate more positive attitudes or larger quantities. An example is shown in the screenshot below. Now, the coding scheme shown above is not really ‘wrong’ in any way. However, we usually prefer higher values indicating more positive attitudes or larger quantities because we find this more […]
When we start analyzing a data file, we first inspect our data for a number of common problems. For instance, we want to be sure that variables have the right formats, don’t contain any weird values and have plausible distributions. The table below proposes which steps should be taken and in which order. For getting […]
A company wants to know how job performance relates to IQ, motivation and social support. They collect data on 60 employees, resulting in job_performance.sav. Part of these data are shown below. Quick Data Check We usually start our analysis with a solid data inspection. Since that’s already been done for the data at hand, we’ll limit it […]
A large bank wants to gain insight into their employees’ job satisfaction. They carried out a survey, the results of which are in bank_clean.sav. The survey included some statements regarding job satisfaction, some of which are shown below. Research Question The main research question for today iswhich factors contribute (most) to overall job satisfaction?as measured by overall (“I’m […]
When running correlations in SPSS, we get the significance levels as well. In some cases, we don’t want that: if our data hold an entire population, such p-values are actually nonsensical. For some stupid reason, we can’t get correlations without significance levels from the correlations dialog. However, this tutorial shows 2 ways for getting them anyway. We’ll use adolescents.sav throughout. Correlation Table as Recommended […]
This tutorial shows how to draw a regression line in SPSS. We encourage you to follow along by downloading and opening job_performance.sav, part of which are shown below. Our data basically just hold job performance scores and IQ, motivation and social support which -supposedly- contribute to job performance. The meaning of our variables is seen under variable view, […]
Running a basic multiple regression analysis in SPSS is simple. For a thorough analysis, however, we want to make sure we satisfy the main assumptions, which are linearity: each predictor has a linear relation with our outcome variable; normality: the prediction errors are normally distributed in the population; homoscedasticity: the variance of the errors is constant in the population. […]
“Inferential statistics” is the branch of statistics that deals with generalizing outcomes from (small) samples to (much larger) populations. Also, “inferential statistics” is the plural for “inferential statistic”Some key concepts are statistical significance testing; confidence intervals; statistical power; null hypotheses; standard errors. All of these basically aim at drawing conclusions (or “inferences”) on populations based on […]
Correlation B Coefficients Intercept Regression Residuals R-Square Simple linear regression is a technique that predicts a metric variable from a linear relation with another metric variable.Remember that “metric variables” refers to variables measured at interval or ratio level. The point here is that calculations -like addition and subtraction- are meaningful on metric variables (“salary” or […]
Multiple regression is a statistical technique that aims to predict a variable of interest from several other variables. The variable that’s predicted is known as the criterion. The variables that predict the criterion are known as predictors. Regression requires metric variables but special techniques are available for using categorical variables as well. Multiple Regression – Example I run a […]
SPSS Regression Basics Simple Linear Regression – Quick Introduction SPSS Multiple Regression Analysis – Tutorial Linear Regression in SPSS – A Simple Example Read SPSS Stepwise Regression Stepwise Regression in SPSS – Data Preparation Read Stepwise Regression in SPSS – Example Stepwise Regression in SPSS – Example 2 Regression – Dummy Variables Creating Dummy Variables […]
Introduction SPSS ships with a manual called “Command Syntax Reference” (or CSR). Whenever you don’t know or understand something, this should usually be the first place to look. SPSS Command Syntax Reference SPSS comes with a syntax reference manual explaining all existing commands. This book (in .pdf format) is called the “Command Syntax Reference” and is mostly […]
Python is among the most important programming languages today and can be used in SPSS. Doing so may truly decimate the time and effort you need to get things done. This tutorial briefly explains what Python is, how it relates to SPSS and why you might want to start using it. What is Python? Python is among the most important […]
