Impact of the coronavirus (COVID-19) pandemic on Consumer Price Index data for December 2020

This page provides further information on the effects of the COVID-19 pandemic for the December 2020 Consumer Price Index news release.

Collection mode

Data collection for December 2020 involved no personal visits, so all data were collected either online or through telephone interviews. An example of this is full-service restaurants; even if a restaurant was open for dine-in service, as well as open for take-out or delivery, the data collector attempted to obtain the price from the restaurant’s website or by telephone call with the respondent, rather than a personal visit.

Table 1. Collection modes for the commodities and services price survey, percent
Month	2019			2020
Month	Personal visit	Telephone	Online	Personal visit	Telephone	Online
March	74	10	16	44	14	42
April	74	10	16	0	18	82
May	74	10	16	0	17	83
June	73	10	17	0	17	83
July	74	10	16	0	17	83
August	73	10	17	0	17	83
September	73	10	17	0	17	83
October	73	10	17	0	16	84
November	73	9	18	0	16	84
December	72	10	18	0	16	84
Average, Feb 2019–Feb 2020	73	10	17

Table 2. Collection modes for the housing survey, percent
Month	2019		2020
Month	Personal visit	Telephone	Personal visit	Telephone
March	36	64	30	70
April	38	62	0	100
May	39	61	0	100
June	38	62	0	100
July	37	63	0	100
August	37	63	0	100
September	38	62	0	100
October	39	61	0	100
November	38	62	0	100
December	39	61	0	100
Average, Feb 2019–Feb 2020	38	62

Response rates

For some CPI market basket categories, the percentage of the sample collected in December 2020 was notably lower than average. These included food from vending machines and mobile vendors, admissions, leased cars and trucks, and new vehicles.

There was a lower percentage of collected rents in December 2020 compared with December 2019.

Table 3. Response rates for the commodities and services price survey, percent
Month	2019		2020
Month	Collected prices	Uncollected prices	Collected prices	Uncollected prices
March	87	13	76	25
April	86	14	65	35
May	87	13	68	32
June	86	14	70	30
July	86	14	70	30
August	86	14	72	28
September	86	14	73	27
October	86	14	74	26
November	87	13	75	25
December	86	14	77	23
Average, Feb 2019–Feb 2020	86	14

Table 4. Response rates for the housing survey, percent
Month	2019			2020
Month	Collected rents	Vacant units	Uncollected rents	Collected rents	Vacant units	Uncollected rents
March	67	6	27	63	5	32
April	68	6	26	61	4	35
May	69	6	25	61	4	35
June	68	6	26	62	4	34
July	69	6	25	60	4	36
August	67	6	27	62	4	34
September	65	6	29	60	4	36
October	69	5	26	59	4	37
November	69	6	25	60	4	36
December	67	6	27	62	4	34
Average, Feb 2019–Feb 2020	68	6	26

Imputation

In December 2020, the CPI continued to impute the majority of uncollected prices from collected prices within the same item and geographic area (home cell). However, the number of prices imputed from a different item area cell (different cell) increased from the same time in 2019. There were no instances where the data from the previous month were imputed to the current month (carry forward).

Table 5. Imputation source for the commodities and services price survey, percent
Month	2019			2020
Month	Home cell	Different cell	Carry forward	Home cell	Different cell	Carry forward
March	94	6	0	90	10	0
April	92	8	0	84	16	0
May	92	8	0	85	15	0
June	92	8	0	86	14	0
July	92	8	0	86	14	0
August	91	9	0	86	14	0
September	93	7	0	87	13	0
October	91	9	0	88	12	0
November	93	7	0	89	11	0
December	92	8	0	88	12	0

Table 6. Imputation source for the housing survey, percent
Month	2019		2020
Month	Noninterview	Vacancy	Noninterview	Vacancy
March	82	18	87	13
April	82	18	90	10
May	82	18	91	9
June	81	19	89	11
July	81	19	89	11
August	83	17	91	9
September	83	17	90	10
October	83	17	90	10
November	82	18	90	10
December	82	18	90	10

Nonvacant units with respondents previously reporting, but not currently reporting, receive noninterview imputation for use in the CPI. Vacant units that were previously occupied by renters are also imputed for use in estimation by separate methods. Table 6 below shows a reduction in vacancy imputation performed in the current month relative to the same time last year.

Cell, series, index, or observation suppression

Table 7 lists the data series that were both inadequate for publication in December 2020 because of insufficient sample and that were adequate over the year before March 2020.

Table 7. List of data inadequate for publication for December 2020
LABSTAT ID	Item	Area
CPI-U Series
CUUR0000SETA03	Leased cars and trucks	U.S. city average
CUUR0000SS62032	Admission to sporting events	U.S. city average
CUUR0360SATCLTB	Transportation commodities less motor fuel	East South Central
CUUR0360SETA	New and used motor vehicles	East South Central
CUUR0360SETA01	New vehicles	East South Central
CUURS23BSAD	Durables	Detroit-Warren-Dearborn, MI
CUURS23BSATCLTB	Transportation commodities less motor fuel	Detroit-Warren-Dearborn, MI
CUURS23BSETA	New and used motor vehicles	Detroit-Warren-Dearborn, MI
CUURS23BSETA01	New vehicles	Detroit-Warren-Dearborn, MI
CUURS35ESAEC	Education and communication commodities	Baltimore-Columbia-Towson, MD
CUURS48ASAM	Medical care	Phoenix-Mesa-Scottsdale, AZ
CUURS48ASATCLTB	Transportation commodities less motor fuel	Phoenix-Mesa-Scottsdale, AZ
CUURS48ASETA	New and used motor vehicles	Phoenix-Mesa-Scottsdale, AZ
CUURS48ASETA01	New vehicles	Phoenix-Mesa-Scottsdale, AZ
CPI-W Series
CWUR0000SETA03	Leased cars and trucks	U.S. city average
CWUR0360SETA01	New vehicles	East South Central
CWURS23BSAGC	Other goods	Detroit-Warren-Dearborn, MI
CWURS23BSETA	New and used motor vehicles	Detroit-Warren-Dearborn, MI
CWURS23BSETA01	New vehicles	Detroit-Warren-Dearborn, MI
CWURS35ESAEC	Education and communication commodities	Baltimore-Columbia-Towson, MD
CWURS48ASAGC	Other goods	Phoenix-Mesa-Scottsdale, AZ
CWURS48ASAM	Medical care	Phoenix-Mesa-Scottsdale, AZ
CWURS48ASETA01	New vehicles	Phoenix-Mesa-Scottsdale, AZ
CWURS49DSAGS	Other personal services	Seattle-Tacoma-Bellevue, WA
C-CPI-U Series
No series were inadequate for publication.
AP Series
APU0000706311	Turkey, frozen, whole, per lb. (453.6 gm)	U.S. city average
APU0000711411	Grapefruit, per lb. (453.6 gm)	U.S. city average
APU0000712211	Lettuce, iceberg, per lb. (453.6 gm)	U.S. city average
APU0000712406	Peppers, sweet, per lb. (453.6 gm)	U.S. city average
APU0000712412	Broccoli, per lb. (453.6 gm)	U.S. city average
APU0000FL2101	Lettuce, romaine, per lb. (453.6 gm)	U.S. city average
APU0100711211	Bananas, per lb. (453.6 gm)	Northeast urban
APU0100711311	Oranges, Navel, per lb. (453.6 gm)	Northeast urban
APU0100711411	Grapefruit, per lb. (453.6 gm)	Northeast urban
APU0100711412	Lemons, per lb. (453.6 gm)	Northeast urban
APU0100711415	Strawberries, dry pint, per 12 oz. (340.2 gm)	Northeast urban
APU0100FJ1101	Milk, low-fat, reduced fat, skim, gallon container	Northeast urban
APU0200702212	Bread, whole wheat, pan, per lb. (453.6 gm)	Midwest urban
APU0200709112	Milk, fresh, whole, fortified, per gal. (3.8 lit)	Midwest urban
APU0200711411	Grapefruit, per lb. (453.6 gm)	Midwest urban
APU0200711412	Lemons, per lb. (453.6 gm)	Midwest urban
APU0200712112	Potatoes, white, per lb. (453.6 gm)	Midwest urban
APU0300701111	Flour, white, all purpose, per lb. (453.6 gm)	South urban
APU0300702212	Bread, whole wheat, pan, per lb. (453.6 gm)	South urban
APU0300703311	Round roast, USDA Choice, boneless, per lb. (453.6 gm)	South urban
APU0300705121	Bologna, all beef or mixed, per lb. (453.6 gm)	South urban
APU0300710411	Ice cream, prepackaged, bulk, regular, per 1/2 gal. (1.9 lit)	South urban
APU0300711311	Oranges, Navel, per lb. (453.6 gm)	South urban
APU0300711411	Grapefruit, per lb. (453.6 gm)	South urban
APU0300711412	Lemons, per lb. (453.6 gm)	South urban
APU0300712211	Lettuce, iceberg, per lb. (453.6 gm)	South urban
APU0300716116	Margarine, soft, tubs, per lb. (453.6 gm)	South urban
APU0300FL2101	Lettuce, romaine, per lb. (453.6 gm)	South urban
APU035072511	Fuel oil #2 per gallon (3.785 liters)	South Atlantic
APU0400702212	Bread, whole wheat, pan, per lb. (453.6 gm)	West urban
APU0400705111	Frankfurters, all meat or all beef, per lb. (453.6 gm)	West urban
APU0400711411	Grapefruit, per lb. (453.6 gm)	West urban
APU0400711412	Lemons, per lb. (453.6 gm)	West urban
APU0400711415	Strawberries, dry pint, per 12 oz. (340.2 gm)	West urban
APU0400714233	Beans, dried, any type, all sizes, per lb. (453.6 gm)	West urban
APU0400FL2101	Lettuce, romaine, per lb. (453.6 gm)	West urban

Measures of error

The standard error of the CPI’s change can be used to construct confidence intervals to determine whether the change for a particular CPI series is significantly different from zero. Table 8 shows the 1- and 12-month standard error for selected indexes at the U.S. level.

Table 8. Impact on standard errors of one- and twelve-month percent changes
Expenditure category	One month		Twelve month
Expenditure category	Dec 2019	Dec 2020	Dec 2019	Dec 2020
All items	0.03	0.03	0.09	0.08
Food and beverages	0.08	0.10	0.13	0.23
Food	0.08	0.10	0.13	0.22
Housing	0.05	0.05	0.13	0.11
Apparel	0.51	0.39	1.05	0.82
Transportation	0.08	0.11	0.15	0.25
Medical care	0.21	0.06	0.66	0.29
Recreation	0.15	0.14	0.33	0.41
Education and communication	0.07	0.06	0.24	0.23
Other goods and services	0.13	0.15	0.35	0.34
Energy	0.11	0.14	0.39	0.23
All items less food and energy	0.04	0.04	0.11	0.09

Last Modified Date: January 13, 2021