The main differences between the indicators provided by CWTS Journal Indicators, in particular the RIP and SNIP indicators, and the journal impact factor (JIF) can be summarized as follows:
SNIP is just one type of measure created by Moed and his team.
Look in this PDF for the descriptions of the types of data represented in the Centre for Science and Technology Studies (CWTS) Journal Indicators at Leiden University.
To compare journals in a specific subject field, follow the steps:
1. Go to CWTS Journal Indicators web site.
2. Click on the Indicators tab.
3. Make your selections from the drop down menus. In this search, the SNIP Indicators for journals in Psychology are shown below.