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Working with the World Values Survey in SPSS
The purpose of replication analysis is to determine if a particular result gleaned from a sample of data can be reproduced with a second sample of similar data. If the results using the same variables from two different samples are similar, we can be more confident that a conclusion we have reached based on the data analysis is likely correct. However, if the results differ, it is necessary to critically assess where there is a problem. Most likely, the problem lies with one or both of the samples used in the analysis. For example, even though the researchers collecting the data may have had tried to achieve a representative sample based on randomization, it is possible that one or both samples fall short of this important goal. As a result, when the ability to generate a true random sample is compromised, a sample is likely not representative of a particular population, and the results from the sample may not be replicable.
Furthermore, it is important to consider the time period in which data was collected for each sample; this is especially true for survey data. The seventh wave of the World Values Survey data for the United States was collected during 2017, while the Dataprac data was collected in the United States in 2019. The difference in time between the two datasets may influence the results to some degree. Importantly, how survey respondents thought about the issues asked in the survey may have differed between the two time periods.
In terms of how the size of a sample influences the results, it is important to note, too, that the seventh wave of the World Values Survey for the United States includes over 2,600 observations, while the Dataprac has a little over 1,000. If both samples are representative, this difference alone makes the World Values Survey superior because the margin of error for any particular sample statistic is lower when the number of observations is higher. This makes the estimates from the larger sample more precise (and hence more likely to be significant if there is indeed a true relationship between variables in the population from which a sample was generated).
It is also possible, too, that some of the questions and potential responses may also differ between the two surveys. While the overwhelming majority of the questions between the Dataprac and World Values Survey are exactly alike, there are a few subtle differences between the two surveys. For example, for the question “Which party would you vote for if there were a national election tomorrow?” the question as worded is the same for the two surveys, but the possible responses differ slightly. Specifically, respondents for the World Values Survey were given additional options from which to choose (such as the Libertarian Party and the Green Party) while the respondents in the Dataprac were not given these additional options. This slight discrepancy might also compromise the comparability of the responses. (Overall, however, the wording of the questions between the Dataprac and World Values Survey is mostly the same.)
Finally, it is important to recognize that obtaining a ‘significant’ result from one sample while the result from the second sample is ‘insignificant’ does not necessarily mean that the significant result is more correct. Rather, it is important to assess these particular issues to assess which dataset might be more representative and hence a more adequate reflection of the population from which the sample was derived.
Downloading the World Values Survey for replication analysis
Go to worldvaluessurvey.org to find the following page.
Click on Data & Documentation on the left hand side of the page.
From here click on Documentation/Downloads.
Click on Wave 7 (2017-2020).
From here, use the slide bar under “Select a country” to find USA 2017.
Click on USA 2017. This will take you to the page where the USA 2017 WVS data is located. Before downloading the data in SPSS, however, you should peruse the ‘questionnaire’ and the ‘codebook and results’ pdf files that are available. The questionnaire lists how each question was asked to survey participants, along with some of the possible responses. Working with the two documents together, you should be able to understand much of the coding scheme in the World Values Survey. It will also be possible, later, to display the codes in SPSS for each variable as well. (Note that responses that are unique to the United States (like Political Party) are not included in the generic questionnaire. You will be able to use the ‘Variable View’ in SPSS to determine the specific codes once you have opened the dataset).
Once you click on USA 2017, you will also see the datasets as they are available for public use. For SPSS, you should choose the last file in the list: WVS Wave 7 United States Spss v1.6. Download this file onto your computer and store it where you can easily find it. Once you unzip the file (by clicking on it), your SPSS program should open the dataset.
Once the dataset is opened, you can use the tutorials from Chapters 7, 8, and 9 to perform the same data analysis using the World Values Survey as you did with the Dataprac. If necessary, be sure to transform any nominal-level variables into binary variables with the same logic as you did for the Dataprac. Also be sure to limit the data to your specific research population before beginning your analysis.