Double-checking NPR's income data

21 Feb 2015

python • pandas • data exploration • income • economics • [archive]

According to NPR.org, “After 1980, only the top 1% saw their incomes rise.” Flowing Data quoted this figure:

You can see the trend more clearly here (note that the y-axis shows growth in year X vs. 1917; so, it’s clear that income growth stagnated for the bottom 90% in the last 40 years):

Their data came from World Top Incomes Database.

I decided to double-check this claim using a dataset from census.gov

Python code:

%matplotlib inline
import pandas as pd
import seaborn as sns
sns.set(context="poster", style="dark")
import mpld3

# csv location = https://github.com/aflyax/Python/blob/master/income/income_2013_dollars.csv
income_df = pd.read_csv("income_2013_dollars.csv", sep='\t', thousands=',')
income_df.columns = ["year", "lowest fifth", "second fifth", "third fifth", "fourth fifth", "top fifth", "top 5%"]
income_df.sort(columns="year", inplace=True)
income_df.head()

	year	lowest fifth	second fifth	third fifth	fourth fifth	top fifth	top 5%
47	1966	14747	32739	46844	62710	107026	164340
46	1967	14977	33490	48138	64560	113997	180362
45	1968	16143	35208	50300	67270	114947	177194
44	1969	16656	36783	52635	70510	120757	185476
43	1970	16404	36271	52445	70744	121652	185243

income_df.tail()

	year	lowest fifth	second fifth	third fifth	fourth fifth	top fifth	top 5%
4	2009	16604	40232	65061	98788	205788	352985
3	2010	15944	39436	64276	98064	199918	334275
2	2011	15828	38898	63212	96563	205003	356839
1	2012	15760	38739	63372	96861	205503	357458
0	2013	16109	39514	63916	97207	206687	358722

ax = income_df.plot(x="year")
ax.set_ylabel("income")
ax.set_xlabel("year")
print("feel free to interact with the graph:")
mpld3.display() # to make interactive graph

income_df[income_df.year.isin([1970, 2000, 2013])]

year	lowest fifth	second fifth	third fifth	fourth fifth	top fifth	top 5%
1970	16404	36271	52445	70744	121652	185243
2000	19103	43678	68646	101170	212266	376138
2013	16109	39514	63916	97207	206687	358722

Conclusion: While it is true that the lowest fifth stagnated since 1970, the second, the third, and the fourth fifths (and, of course, the top fifth) increased their income. (Although all groups, including the top 5%, seem to have stagnated since 2000.)

This is a slightly different story from “after 1980, only the top 1% saw their incomes rise”. (It is also beside the point that neither NPR’s nor the above graph show mobility. I.e., the same person in 1970 and today is unlikely to belong to the same “income class”. These data also do not include any information on immigration or unemployment.)

Notebook for this code is here.

{data dendrites} exploring data science with Python et al.

Double-checking NPR's income data