4 Bad Things Decreasing - Part I
In the next series of blog posts, I will visualize trends of some of the bad things that happen in the world. And with that, I will try to showcase the improvements that often go unnoticed.
Trend, by definition, means how something changes with respect to time. A positive or increasing trend happens when the quantity or the magnitude increases as time progresses while a negative or decreasing trend signifies a decreasing pattern as time progresses.
Fig: Trends of Idle capacity of machines 
Trends are often represented with trendlines, which are made by connecting the observation points on a plot. To find the generalized trend, people sometimes prefer connecting just the start and the end observations over the relevant time period. Other times, trends could be calculated by optimizing/minimizing some heuristics or errors, like RMSE.
In the first part of this series, you will see -
1) How much we have been successful in abolishing forced labor. 
Counting the number of countries where forced labor is legal is defined when there’s no law or constitution prohibiting forced labor or serfdom, and the country hasn’t yet signed any UN convention banning forced labor.
2) Accelerated reduction of the price of solar panels  making them accessible to a large population and promoting clean solar energy alternatives.
3) A sharp cut in the amount of oil spilled  which was once the leading cause of tremendous destruction to the natural habitat of aquatic life. Thanks to several regulations and the development of new technologies, we are past that.
4) Success in controlling the HIV epidemic. 
Check out my interactive Tableau dashboard below.
You can view a better version here - https://public.tableau.com/views/4BadThingsPart-I/Dashboard?:language=en-US&:display_count=n&:origin=viz_share_link
 Trendline of Idle capacity of the machine, i.e. the capacity which is not being utilized. www.vizoftheweek.com/single-post/Predictive-Maintenance-of-a-Machine
 Legal slavery data—v1. gapm.io/islav; http://gapm.io/d_lslave
 Solar photovoltaic (PV) data for the years 1976-2009 are sourced from Lafond et al. (2017). The authors sourced this data from the Navigant Research series - www.navigantresearch.com/
Prices from LaFond et al. (2017) have been converted to 2019 US$ using the US GDP deflator
 ITOPF (International Tanker Owners Pollution Federation). “Oil tanker spill statistics 2016.” Page 4. Published February 2017. Accessed September 20, 2017.
 unaids.org - https://www.unaids.org/en/resources/fact-sheet; http://www.unaids.org/sites/default/files/media_asset/HIV_estimates_from_1990-to-present.xlsx