Determining Cost and Time Performance Indexes for Diversified Investment Tasks
Round 1
Reviewer 1 Report
This was a well-written manuscript, which focused primarily to develop a method that enables the analysis and evaluation of deviations at the stage of implementing a construction investment in various construction sectors. The above method used the Earned Value Method (EVM). The article attempts to prove the validity of the assumption about the necessity of the cyclical verification of the level of deviations of works.
I found article very interesting. The research design is appropriate. The title of the paper reflects its content. The methodology is very well explained.
Since the author claims the drawn conclusions are not universal for all construction sectors. Perhaps this is a topic for future research?
The document must be carefully checked as there are some inaccuracies and style errors. Also I recommend to change the name of Figure 2. e.g. The graphic interpretation of the boxplot.
Author Response
Wrocław, Poland, 28th July 2022
Dear Reviewer of Buildings, MDPI
Thank you for the review of my paper buildings-1840468 entitled “Determining Cost and Time Performance Indexes for Diversified Investment Tasks” to be published in the journal Buildings, special issue “Construction Scheduling, Quality and Risk Management”.
I appreciate your thoughtful and accurate comments as well as appreciation of my research works. I have carefully considered all comments and have now completed the revisions incorporating your suggestions in the revised uploaded manuscript.
I hope that the revised paper meets your expectations.
Kind regards,
Prof. Dr Jarosław Konior
Department of Building Engineering, Faculty of Civil Engineering, Wroclaw University of Science and Technology, 50-370 Wrocław, Poland
Here are answers to reviewer’s comments:
REVIEWER 1
General Comments. This was a well-written manuscript, which focused primarily to develop a method that enables the analysis and evaluation of deviations at the stage of implementing a construction investment in various construction sectors. The above method used the Earned Value Method (EVM). The article attempts to prove the validity of the assumption about the necessity of the cyclical verification of the level of deviations of works.
I found article very interesting. The research design is appropriate. The title of the paper reflects its content. The methodology is very well explained.
Answer to General Comments. Thank the reviewer for a positive view on my submission to Buildings as well as well balanced appreciation of my research works outputs presented in the article.
Comment 1. Since the author claims the drawn conclusions are not universal for all construction sectors. Perhaps this is a topic for future research?
Answer 1. Yes, indeed. Drawn conclusions are not universal for all construction sectors due to two reasons: the analysed projects represent on site observations rather than a statistical sample (1) and some construction sectors are not comparable to one another, e.g. residential hosing to logistic centers (2). In the article, the analysis was only carried out for three groups of buildings. It is justified to continue research related to the course of cash flows and cost planning for various building facilities, e.g. collective housing buildings, commercial and service facilities, etc. The developed methodology for planning the course of the cumulative cost curve in construction projects will enable the formulation of simpler and more accurate methods of planning implementation costs of multiple investment tasks in the construction industry. The proposed original methodology for planning the course of the cumulative cost curve in construction projects uses a method of shaping the S-curve, which is known in both literature and in a practical approach. Knowing the total cost and duration of the planned construction project, which is determined on the basis of the project documentation and cost estimates, and by using the proposed 6th degree polynomial of actual costs, it is possible to plan costs correctly and determine the planned monthly work and expenditure amounts.
Comment 2. The document must be carefully checked as there are some inaccuracies and style errors.
Answer 2. The manuscript has been checked and improved by the English native representing Department of Foreign Languages of Wroclaw University of Science and Technology. We hope that now the English is correct, readable and more comprehensive.
Comment 3. Also I recommend to change the name of Figure 2. e.g. The graphic interpretation of the boxplot.
Answer 3. Good point, thank you. The name of the figure 2 has been changed accordingly: The graphic interpretation of the boxplot.
Author Response File: 
Author Response.pdf
Reviewer 2 Report
The paper is reasonable but not innovative in any way. It basically just explains EVM and gives and example comparing 3 groups of project types.
I felt the article gave a wrong level of expectation. That it was going to share a new method of EVM, which I did not find in the article.
In the abstract it stated, 'The article attempts to prove the validity of the assumption about the necessity of the cyclical verification of the level of deviations of works.' It was not clear what this meant and did not see any attempted proof in the article!
My overall recommendation is it should go ahead because it has some merit, but it should review the abstract and align more clearly with the article. It seems very much like a basic article on EVM with some examples analysis.
Author Response
Wrocław, Poland, 28th July 2022
Dear Reviewer of Buildings, MDPI
Thank you for the review of my paper buildings-1840468 entitled “Determining Cost and Time Performance Indexes for Diversified Investment Tasks” to be published in the journal Buildings, special issue “Construction Scheduling, Quality and Risk Management”.
I appreciate your thoughtful and accurate comments as well as appreciation of my research works. I have carefully considered all comments and have now completed the revisions incorporating your suggestions in the revised uploaded manuscript.
I hope that the revised paper meets your expectations.
Kind regards,
Prof. Dr Jarosław Konior
Department of Building Engineering, Faculty of Civil Engineering, Wroclaw University of Science and Technology, 50-370 Wrocław, Poland
Here are answers to reviewer’s comments:
REVIEWER 2
General Comments. The paper is reasonable but not innovative in any way. It basically just explains EVM and gives and example comparing 3 groups of project types. My overall recommendation is it should go ahead because it has some merit, but it should review the abstract and align more clearly with the article. It seems very much like a basic article on EVM with some examples analysis.
Answer to General Comments. I appreciate the reviewer’s valuable view on the presented topic but cannot agree to full extant. As a matter of fact the research works analysed and their outputs presented in results and conclusions used EVM only as a tool, well known construction management approach. The article presents the simplest possible model for determining the curve of cumulative costs of construction works and its consideration / solution by means of boxplot interpretation. By using the processed data, it is possible to develop boxplots for the analyzed performance indexes. The boxplot is used to present the results and to compare data, and it contains information about the position, dispersion, and shape of the data distribution. The model is practical and easy-to-apply, because it was developed as a result of the authors' own measurements of the cumulative values of the amount of construction works and costs in cyclical, coherent and verified audit reports of the Bank Investment Supervision.
Comment 1. I felt the article gave a wrong level of expectation. That it was going to share a new method of EVM, which I did not find in the article.
Answer 1. I cannot thoroughly agree with the comment, I am sorry. Nowhere in the paper it is stated that a new method of EVM has been presented or applied for a new analysis. The proposed original methodology for planning the course of the cumulative cost curve in construction projects uses a method of shaping the S-curve, which is known in both literature and in a practical approach. Knowing the total cost and duration of the planned construction project, which is determined on the basis of the project documentation and cost estimates, and by using the proposed boxplots breakdown in 4 quartiles, it is possible to determine deviations / variations of cost and time of construction works. Those have absolutely crucial practical implications for projection of budget and schedule parameters of future projects. on the basis of a few simple parameters (EV, PV, AC), and the resulting indexes (CPI, SPI, EAC, ETTC), the actual progress of construction projects can be quickly assessed. The analysis of CV cost deviation and SV time deviation indexes allows for the proper management of investment projects. The obtained values enable the work and expenditure schedule to be properly planned in order to correctly estimate the actual costs and the deadline of investments. The conducted analyzes for three groups of objects show a great similarity in the obtained parameters and indexes. Research indicates that the problem of exceeding the planned budget, and failure to meet the planned deadlines, is common, regardless of the type of investment.
Comment 2. In the abstract it stated, 'The article attempts to prove the validity of the assumption about the necessity of the cyclical verification of the level of deviations of works.' It was not clear what this meant and did not see any attempted proof in the article!
Answer 2. Well, as a matter of fact the statement is actually misleading. I meant … the level of cost and time variances, not deviations of works. Thank you for spotting the incorrect meaning, especially that it was stated in the eye catching abstract. The mistake was corrected in the revised manuscript accordingly. Having said that there is plenty of budget and schedule deviations proofs in the paper, also determined in broken down boxplots 4 quartiles:
- in terms of cost:
- In the analyzed 14 projects, 50% of them were implemented with their budget exceeding the planned value. For these projects, the cost performance index during the entire implementation period differed from the value of 1 (CPI <1),
- The largest deviations of the cost performance index can be noticed for group 2 and group 3 of the analyzed projects, i.e. for hotel buildings and commercial and service buildings. In group 2, over 88% of projects (8 out of 9 cases) were implemented above the planned budget, and in group 3 - 50% of projects (4 out of 8 cases) were implemented above the planned budget.
- in terms of time:
- The analysis of the use of the schedule performance index confirms that the estimated duration stabilizes in the second period, i.e. after about half of the planned time. The scope of the obtained deviations from the schedule indexes is within an area that is limited from the top and bottom by the power curve trend line.
- The planned duration was exceeded in 86% of cases, i.e. in 24 out of 28 of the analyzed investments
Author Response File: Author Response.pdf
