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README.md

BD Economics Current Population Survey Extract

v0.2, updated: January 23, 2019

Working with CPS microdata using jupyter notebooks and python.

Brian Dew, @bd_econ


Example

Input (after running programs on raw data downloaded from Census):

import pandas as pd

df = pd.read_feather('cps2017.ft').query('MONTH == 10 and 25 <= AGE <= 54')
df.groupby('EDUC').PWSSWGT.sum()

Output:

EDUC

ADV     16551343.0
COLL    30948892.0
HS      33313412.0
LTHS    11389192.0
SC      33637956.0

Name: PWSSWGT, dtype: float32

The above arbitrary example calculates how many age 25-54 people are in each of five educational categories in October 2017. For example, about 16.6 million have advanced degrees.

Overview

UPDATE: v0.2 released. Currently, the project includes jupyter notebooks for working with monthly Current Population Survey public use microdata files. The microdata files can be downloaded from the US Census Bureau's CPS FTP page.

The three notebooks are:

  1. bd_CPS_dd.ipynb reads settings from bd_CPS_details.py and creates a python dictionary with information needed to read the raw CPS microdata files in the next step, and adjust them to be more time consistent and useful. The program requires downloading the CPS data dictionary text files from the FTP page.

  2. bd_CPS_reader.ipynb reads the raw monthy CPS microdata files downloaded from Census and converts them into annual feather format files that can be read by python or R. The feather format is particularly fast when the data are mostly integers or categorical, as in this case.

  3. bd_CPS_grapher.ipynb creates line plots from the bd CPS feather file data and user-specified query strings. This program allows a user to query the (currently 1994-) dataset, apply calculations, and visualize the results.

Settings and other required code are also contained in the python file bd_CPS_details.py. There is additionally a notebook that downloads regional consumer price index data from BLS (used as the price deflator for real wage series), as well as a notebook that benchmarks the bd CPS results against four BLS published estimates. If you want to see examples of how to use bd CPS data, the benchmarks are a good place to start.

How to run/ update

Sometime in the middle of each month, the Census Bureau will release the previous month's CPS microdata in a compressed file on the US CPS FTP page. The full set of 1994 onward monthly microdata files are available to download on the FTP page. For the bd CPS program to work, a local folder must contain the relevant unzipped CPS microdata files. Next, the data dictionary files that correspond to each microdata file should be downloaded and stored in the same folder as the microdata. Separately, to adjust wages for inflation the CPI for each of four US regions should be downloaded using the notebook bd_CPS_cpi.ipynb.

The first step in generating the bd CPS is to run the data dictionary generator, which creates a pickled python dictionary that provides information needed for reading the raw monthly CPS microdata files. This is done by running the notebook called bd_CPS_dd.ipynb. To run the bd CPS for 2000, 2001, and 2002, which utilize revised 2000-based weights, you'll also need to run bd_CPS_2000-based_weights.ipynb.

The next step is to run the notebook called bd_CPS_reader.ipynb. This will create a feather file called cpsYYYY.ft for each year included in the command in the bd_CPS_reader notebook. The feather file can be read into pandas as a dataframe, and, as I understand but have not tested, can be read into R and other statistical software programs. The file contains a subset of variables that are most commonly used for research.

bd CPS variables

The bd CPS contains several variables that are recodes of other CPS variables or combinations of CPS data and outside data. The two most important examples of this are the Labor Market Status (LMSTAT) and the real wage variables (RHRWAGE and RWKWAGE).

Details on bd CPS variables are as follows:

  • LMSTAT - Labor market status - Classifies all age 16+ observations into one of 12 labor market statuses. See bd_CPS_reader.ipynb for mapping.
  • RHRWAGE - Real hourly wage - Available in ORG quartersample, this converts weekly pay to hourly where possible and then adjusts the wage using the not-seasonally-adjusted regional CPI (Northeast, Midwest, South, West).
  • RWKWAGE - Real weekly wage - Same as above, except the weekly pay (therefore factoring in hours worked).
  • INDGRP - Industry group of first job - Consistent industry groups for first job: Construction and mining (also includes agriculture and the like), Manufacturing, Trade, transportation, and utilties, Finance and business services (also includes Information and the like), Leisure and hospitality, and Public administration. See bd_CPS_reader.ipynb for mapping.
  • UNEMPTYPE - type of unemployment: job loser, job leaver, new entrant, or re-entrant.
  • UNEMPDUR - duration of unemployment, in weeks.
  • VETERAN - binary variable equal to 1 if served active duty armed forces.
  • CERT - has a professional certification.
  • STATE - converstion of state FIPS code to two letter state abbreviation.
  • EDUC - Highest level of education obtained - Maps the educational categories to five groups: Less than high school, High school, Some college, Bachelor degree, Advanced degree.
  • WBHAO - race/ethnic group - Each observation is mapped to one of five racial/ethnic groups: White, Black, Hispanic, Asian, and Other. White is white non-Hispanic only, black is any black non-Hispanic, Asian is any Asian but not black and non-Hispanic, Other is Native American, Native Hawaiian, Pacific Islander, and other groups. Hispanic is someone of Hispanic ethncity of any race.
  • WBHAOM - race/ethnic group - white, non-Hispanic only, black, non-Hispanic only, Asian or Pacific Islander, non-Hispanic only, Native American, non-Hispanic only, persons of more than one racial group but non-Hispanic, and Hispanic, and race/ethnicity.
  • MARRIED - binary variable equal to 1 if married and otherwise 0.
  • FORBORN - binary variable equal to 1 if born outside the US and otherwise 0.
  • EMP - binary variable equal to 1 if employed and otherwise 0.
  • SCHENR - binary variable equal to 1 if enrolled in high school, college, or university and otherwise 0.
  • PTECON - binary variable equal to 1 if usually part-time for economic reasons and otherwise 0.
  • PRNMCHLD - number of own children under age 18.
  • BASICWGT - weight equal to PWSSWGT before 1998 and PWCMPWGT after. The weight variables use the 2000-based revised weights for the years 2000-2002.
Long-term road map

A crude long-term road map includes the following: refactoring for speed, much expanded graphing capabilities, flexibility in aggregation types/periods, Panel storage of multiple records from same household, CPS matching of observations, including the CPS ASEC, including the CPS supplements, going back to at least 1989, enhanced documentation, and more. See active issues on the project's github repo.

Acknowlegements

Many many thanks to John Schmitt for countless hours of kind and patient guidance. Many thanks to the staff and management of CEPR for giving me the chance to learn about the CPS. Thanks to EPI for providing and sharing very helpful documentation. Thanks to NBER, FRBATL, FRBKC, IPUMS, Urban Institute, Tom Augspurger, and of course the wonderful staff of BLS and Census, for making analysis of the CPS possible for normal people like me by providing useful information.

Contact me

I would really appreciate feedback, especially if you spot an error. I also welcome opportunities to work with people on projects that might make use of these notebooks. Feel free to email me at brianwdew@gmail.com.


List of CPS related links

BLS regional CPI

CEPR data CPS extracts

FRBATL Labor Market Status Categorization

FRBKC Psuedocode

US Census Bureau's CPS FTP page

NBER CPS Basic Data

NBER CPS Supplements

Tom Augspurger CPS in Python examples:

Part 1: Using Python to tackle the CPS

Part 2: Using Python to tackle the CPS

Part 3: Using Python to tackle the CPS

Part 4: Using Python to tackle the CPS