Real sale prices vs. displayed prices :
an issue to consider before expanding scanner
data to other sectors than food products
French scanner data project
Isabelle LEONARD
Project manager for statistical issues
Insee
2015/10/01
French scanner data project
Objective :
Computing an index using scanner data
for industrial food products, health and beauty, and home care products
sold in mass-market retail stores in métropolitan France
without changing the current concepts of the CPI
 Laspeyres index, chained annualy
Basket up-dated at the beginning of each year
Weight computed from the turnovers of the previous year
Replacements of products during the year with a quality-adjustment
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European scanner data workshop
2015/10/01
The phases of a project at Insee
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European scanner data workshop
2015/10/01
A first test in 2011
Goal : checking of the prices provided in the scanner data
Method :
search for the products collected in outlets
in a sample of scanner data (10 families of products sold in 1000 outlets)
by teams in offices that compared the descriptions of the products in the
collection and in scanner data
Results :
Number of products
%
Identical prices
208
60
Prices difference < 5%
51
15
Prices difference > 5% or
failure to find the product
86
25
345
100
Total
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European scanner data workshop
2015/10/01
A second test in 2014
A new method to correct two problems in the first test :
– Using the GTIN to identify products in the collection
– Using daily scanner data prices (v.s. weekly average prices)
Aims of the 2nd test :
– Is the GTIN a reliable identifier for items?
– Are the prices in scanner data close to the prices in collection?
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European scanner data workshop
2015/10/01
The management of the test
• When ?
From the 2nd until the 27th of june 2014
6
•
Where?
in supermarkets and hypermarkets of metropolitan France
(Only the stores of the firms that agree to send their scanner data to Insee)
•
How?
The barcodes of the items were scanned by price collectors at the same
time they collected the prices of all products of the CPI
European scanner data workshop
2015/10/01
The search for sales in scanner data
• 1021 barcodes scanned in 40 outlets
• Research for a sale
from the 5th of may until the 27th of july
independently of the date of the collection
the sale retained is closest to the date of the collection
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European scanner data workshop
2015/10/01
Results of the test
8
Number of products
%
Identical prices
829
81,3
Different prices
124
12,1
No sale
35
3,4
The barcodes don’t translate a GTIN
33
3,2
TOTAL
1021
100,0
European scanner data workshop
2015/10/01
Products not sold during the 3 months
Number of
products not sold
Number of
products sold
% of products
not sold
Food products
1
526
0,2
Manufactured goods
12
234
4,9
Clothing
13
128
9,2
Durables goods
9
65
12,2
35
953
3,5
Sectors
Total
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European scanner data workshop
2015/10/01
Period between the sale and the collection
% of products sold
from
8
until
49
days
from
1
until
7
days
the
same
day
before
than
from
8
until
49
days
after
Number
of
matched
barcodes
Max
length
before the
collection
Max
length
after the
collection
the collection
sectors
Food products
1.1
8.6
80.4
9.3
0.6
526
23
14
Manufactured goods
10.3
21.4
36.8
23.1
8.5
234
43
37
Clothing
16.4
21.9
10.2
21.1
30.5
128
35
18
Durable goods
10.8
15.4
10.8
16.9
46.2
65
27
49
6,1
14,0
55,5
14,8
9.7
953
Total
10
from
1
until
7
days
European scanner data workshop
2015/10/01
Différent dates, more different prices?
Products sold
the same day
another day
than the collection
Number of
products
Number of
products
sold at
different
prices
Number of
products
Number of
products
sold at
different
prices
%
%
Food products
423
42
9,9
103
8
7,8
Manufactured goods
86
5
5,8
148
13
8,9
Clothing
13
5
38,5
115
34
29,6
Durable goods
7
1
14,3
58
15
25,9
529
53
10,0
424
70
16,7
sector
Total
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European scanner data workshop
2015/10/01
Results and limits
•
Less sales in clothing and durables goods
– Many days without sales of a precise product
– For some items, no sales during a long period
but no evident consequences on prices
•
The limits of the study
– Few products in durable goods and clothing (215)
– July (the month after the test) is a sales period in France
– No specialised store in the sample of outlet
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European scanner data workshop
2015/10/01
Thank you for your attention !
Insee
18 bd Adolphe-Pinard
75675 Paris Cedex 14
www.insee.fr
Contact
Isabelle Léonard
Tél. : 01 41 17 68 05
Courriel :[email protected]
Informations statistiques :
www.insee.fr / Contacter l’Insee
09 72 72 4000
(coût d’un appel local)
du lundi au vendredi de 9h00 à 17h00