Reviewer has chosen not to be AnonymousOverall Impression:
UndecidedTechnical Quality of the paper:
Limited noveltyData availability:
All used and produced data (if any) are FAIR and openly available in established data repositoriesLength of the manuscript:
The length of this manuscript is about right
Summary of paper in a few sentences:
As digital economy and particularly, e-commerce, seems to experience a rapid growth in recent years in Southeast Asia, in this article the authors propose to include data from the online marketplaces available in Indonesia to compute commodity-level and expenditure group-level CPI (Consumer Price Index). Moreover, the authors propose to compare these two computed CPIs from the online marketplaces to the CPI computed using the data from BPS-Statistics Indonesia, a non-ministerial government agency that conducts various studies, among which is the calculation of CPI per commodity baskets per city. This comparison between different CPI calculations (from the online marketplaces to the statistics collected by onsite retailers by BPS) is interesting in the context of the rapidly evolving online market and also to see if and how the e-commerce affects the CPI.
Reasons to accept:
- the general idea of the article is interesting, especially in the context of the evolving e-commerce market.
- the presentation of the general and some particular workflows (the "...Flow" diagrams as they are titled in the article) is clear, despite having some that do not provide a lot of information, like the ones in Figure 3 and 4.
- the data used is available in a github repository.
- the authors seem to undersell their results and work by presenting and structuring them in a way that seems lacking. If more explanations and interpretations would be given for certain figures, tables and the results presented there, also showing why they are important and what they show, that would improve the article a lot.
Reasons to reject:
- in the end the authors seem to fail to present the results in a clear manner and the discussion and interpretation about these results seems to be lacking. For example, despite presenting/emphasizing the "red chilli pepper" example in Malang in Table 4, it would have been interesting to see why this is the case and also discussing some of the other commodity cases instead of mentioning the value of the BPS-Statistics CPI vs. the Marketplace CPI (43.86 vs. 60.97), numbers which do not mean a lot as long as they are not put into context; what do these numbers mean, what does the difference between them mean? Are they expected in the economical and "cultural" context of Indonesia, for example?
- some revisions in terms of the usage of English language might be needed. Some sentences lack a verb while the use of articles ("a/an" and "the") is completely missing in some sentences.
- the figures and tables presented are sometimes confusing, also the use of the English language needs to be reviewed as sometimes the explanations (when present) are confusing due to the language used. Also, the presence of some figures might not be necessary as they are now and they seem to be confusing or not have any added value as long as they are not put into context or have more explanations attached to them; e.g. Figure 2 and Figure 8.
- in Table 1 the differentiator and the explanations are unclear at times.
- values from Table 3 require more explanations as it is not clear what the numbers mean; if the emphasis is on the comparison between the BPS-statistics and the Marketplace Coverages, then this needs to be explained in text as well. Also, what is the Final Coverage column and what does it represent?
- Figure 9 is confusing. You introduce the notion of "movement pattern" without explaining what this is and why it is important and the explanation of this figure seems to be lacking. Also, how the aggregate numbers of events are computed is confusing. The subfigures need some explanations or translation (what does the oy axis represent?!).The conclusion ("This means that the movement of marketplace data consumption is more volatile than the pattern of consumption values obtained from BPS-Statistics") illustrates very well the purpose of the figure and what it wants to show, but I felt it could have been explained maybe from the start to show why such a figure would be important.
- the legend of Figures 10, 11 and 12 seems a bit "out of focus", meaning, it can be put somewhere more visible. Also, some inconsistencies are present in some figures, for example, why are the numbers from BPS-Statistics in blue, while the ones from the Marketplace CPI are in orange (the color of BPS-Statistics column)?
- some references need to be revised (see, for example, in the "Data Collection" -> "Documents" section; the references mentioned in points 3 and 4 seem to be wrong, maybe references  and  should be there instead of  and ).
The article needs major revisions to be accepted, in my opinion. I think the following need special attention: the use of English language, the figure and table presentations (some of which might need to be removed if they do not bring useful information), adding more explanations and interpretations to the results.