  This article introduces Unsub Extender, a free tool to help libraries analyze
their Unsub data export files. Unsub is a collection development dashboard that
gathers and forecasts journal-level usage metrics to provide academic libraries
with deeper measurements than traditional cost-per-use. Unsub gives libraries
richer and more nuanced data to analyze their subscriptions, but it does not
include a way to easily visualize the complex and interrelated data points it
provides. Unsub Extender (https://unsubextender.lib.iastate.edu) is a free
Python-based web application that takes an Unsub export file and automates the
creation of interactive plots and visualizations. The tool loads with example
data to explore, and users upload their specific Unsub file to quickly populate
the pre-made plots with actual data. Graphs are interactive, live-updating, and
support zoom, click-and-drag, and hover. Filters are specified through sliders
to model scenarios and focus on areas of interest. A drop-down menu allows
users to change a journal's decision status, and graphs update automatically.
After evaluating journals, users can export the modified dataset to save their
decisions. Unsub Extender proposes best practice in analyzing the increasingly
common Unsub export file. It simplifies the analysis, eliminates duplication of
effort, and enables libraries worldwide to make better, more data-driven
decisions.
