Zastosowanie danych scrapowanych w pomiarze dynamiki cen

Juszczak, Adam

doi:10.18778/0208-6018.352.02

Cited by 3 publications

(2 citation statements)

References 15 publications

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“…Some of them do not require programming skills from the users. However, these methods are less precise -for example, the programs are less likely to take the best object class from the code (Juszczak, 2021). This could lead to gaps in the collected data if the website has a dynamic code or has been subjected to minor corrections.…”

Section: Technical Aspects Of Web Scraping and Practical Usage In Inf...mentioning

confidence: 99%

The use of web-scraped data to analyse the dynamics of clothing and footwear prices

Juszczak

2023

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Web scraping is a technique that makes it possible to obtain information from websites automatically. As online shopping grows in popularity, it became an abundant source of information on the prices of goods sold by retailers. The use of scraped data usually allows, in addition to a significant reduction of costs of price research, the improvement of the precision of inflation estimates and real-time tracking. For this reason, web scraping is a popular research tool both for statistical centers (Eurostat, British Office of National Statistics, Belgian Statbel) and universities (e.g. the Billion Prices Project conducted at Massachusetts Institute of Technology). However, the use of scraped data to calculate inflation brings about many challenges at the stage of their collection, processing, and aggregation. The aim of the study is to compare various methods of calculating price indices of clothing and footwear on the basis of scraped data. Using data from one of the largest online stores selling clothing and footwear for the period of February 2018–November 2019, the author compared the results of the Jevons chain index, the GEKS-J index and the GEKS-J expanding and updating window methods. As a result of the calculations, a high chain index drift was confirmed, and very similar results were found using the extension methods and the updated calculation window (excluding the FBEW method).

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Section: Technical Aspects Of Web Scraping and Practical Usage In Inf...mentioning

confidence: 99%

The use of web-scraped data to analyse the dynamics of clothing and footwear prices

Juszczak

2023

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Section: Technical Aspects Of Web Scraping and Practical Usage In Inf...mentioning

confidence: 99%

Untitled

2023

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One of the ways to raise budget revenue from taxes involves sealing the tax system. This includes eliminating evasion of the payment of excise duty on tobacco products, especially traditional cigarettes and tobacco used for roll-your-own cigarettes. The aim of the research described in the article is to estimate the excise duty gap on tobacco products in Poland on the basis of a survey addressed directly to consumers. The data were drawn from reports prepared for the Polish Chief Sanitary Inspectorate (Pol. Główny Inspektorat Sanitarny -GIS), covering the years 2013, 2015, 2017 and 2019. The number of consumed traditional and roll-your-own cigarettes was calculated. Therefore, the estimates are more consistent with the definition of a tax gap as they include the consumption of roll-your-own cigarettes. According to the research, the excise duty gap on tobacco products was relatively stable between 2013 and 2017 (fluctuating from PLN 5.69 bn to PLN 6.98 bn) and then dropped considerably in 2019 (to PLN 0.94 bn). Nonetheless, increasing the state budget revenue from excise duty on tobacco products is still possible. The growth in the number of smokers in the years 2021 and 2022 allowed the predication that, if other conditions remained the same, the excise duty gap in 2022 would increase in comparison to 2019.

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The use of web-scraped data to analyze the dynamics of footwear prices

Juszczak

2021

JEM

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Aim/purpose – Web-scraping is a technique used to automatically extract data from websites. After the rise-up of online shopping, it allows the acquisition of information about prices of goods sold by retailers such as supermarkets or internet shops. This study examines the possibility of using web-scrapped data from one clothing store. It aims at comparing known price index formulas being implemented to the web-scraping case and verifying their sensitivity on the choice of data filter type. Design/methodology/approach – The author uses the price data scrapped from one of the biggest online shops in Poland. The data were obtained as part of eCPI (electronic Consumer Price Index) project conducted by the National Bank of Poland. The author decided to select three types of products for this analysis – female ballerinas, male shoes, and male oxfords to compare their prices in over one-year time period. Six price indexes were used for calculation – The Jevons and Dutot indexes with their chain and GEKS (acronym from the names of creators – Gini–Éltető–Köves–Szulc) versions. Apart from the analysis conducted on a full data set, the author introduced filters to remove outliers. Findings – Clothing and footwear are considered one of the most difficult groups of goods to measure price change indexes due to high product churn, which undermines the possibility to use the traditional Jevons and Dutot indexes. However, it is possible to use chained indexes and GEKS indexes instead. Still, these indexes are fairly sensitive to large price changes. As observed in case of both product groups, the results provided by the GEKS and chained versions of indexes were different, which could lead to conclu- sion that even though they are lending promising results, they could be better suited for other COICOP (Classification of Individual Consumption by Purpose) groups. Research implications/limitations – The findings of the paper showed that usage of filters did not significantly reduce the difference between price indexes based on GEKS and chain formulas. Originality/value/contribution – The usage of web-scrapped data is a fairly new topic in the literature. Research on the possibility of using different price indexes provides useful insights for future usage of these data by statistics offices. Keywords: inflation, CPI, web-scraping, online shopping, big data. JEL Classification: C43, C49

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Zastosowanie danych scrapowanych w pomiarze dynamiki cen

Cited by 3 publications

References 15 publications

The use of web-scraped data to analyse the dynamics of clothing and footwear prices

The use of web-scraped data to analyse the dynamics of clothing and footwear prices

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The use of web-scraped data to analyze the dynamics of footwear prices

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