Methodology and Quality Update

Latest Update on Methodology and Quality

21/05/2025

Statistical Presentation

Data description

 The Construction Cost Index (CCI) presents data on construction input costs in Saudi Arabia.
•    Setting objectives:
-   Measuring changes in construction costs for materials, labor, and rental of machinery, and equipment.
-   Providing accurate data for economic analysis and decision-making.
•    Choosing a base year:
Choosing a reference year (base year) to calculate the index, which reflects a stable state of the economy, which is 2023.
•    Classification of products:
-  Divide products into groups and categories based on their nature and use. 
-   Adopting the Saudi Classification of Economic Activities (ISIC) and the Central Product Classification (CPC).
•    Calculating the weights:
Calculating the weights of activities and products based on their contribution to the local economy using the results of the 2023 Structural Survey and the 2023 National Accounts Value Added data.
•    Collecting the prices: 
-   Collecting product prices periodically (monthly) to ensure the continuous update of the index through data collection (field-based CAPI).
-    Using selling prices provided by contracting offices, engineering offices, and construction material stores.
•    Calculating the index: 
Applying the Laspeyres equation to calculate the index.
•    Analyzing data:
Analyzing the collected data to understand price changes, interpreting the results, and providing periodic reports.
•    Publishing the results:
Regularly publishing the index results through reports and publications issued by the General Authority for Statistics.
•    Providing Data to Economic Analysts and Decision-makers.

Classification system

The following classifications are applied in the Construction Cost Index.
The National Classification for Economic Activities (ISIC4):
It is a statistical classification based on the International Standard Industrial Classification of All Economic Activities (ISIC4) used to describe the productive activities of an establishment. 
The Central Product Classification (CPC2):
The CPC is a complete classification of products that includes goods and services, the purpose of which is to compile and classify all types of data that require product details.
Metadata are collected through interviews, so that outputs can be produces in accordance with all relevant classifications.
The classifications are available on the GASTAT’s website: www.stats.gov.sa

Sector coverage

The Construction Cost Index covers the following main economic sectors:
•    Costs of basic construction materials.
•    Labor costs.
•    Costs of renting equipment and machinery (with operator/without operator).
•    Energy costs.
The classification of size in this survey is divided into three categories based on the size of the establishment as follows:
•    Small enterprises:
It includes all establishments in which the number of workers ranges between (6-49) workers.
•    Medium enterprises:
It includes all establishments in which the number of workers ranges between (50-249) workers.
•    Large-sized:
It includes all establishments in which the number of workers is more than (250) workers.

Statistical concepts and definitions

Terms and concepts of the Construction Cost Index (CCI):
•    Construction Cost Index (CCI):
A relative figure that measures changes in construction costs over two time periods for a basket of construction materials and services. It is a key index relied upon by planners and researchers in the fields of development and production.
•    Monthly rate of change: 
A rate that reflects the relative monthly changes in the prices of goods and services between the current month and the previous month.
•    Annual rate of change:
An index that reflects the annual relative changes in prices of goods and services between the target month and the same month of the previous year.
•    Goods:
It is a collection of products produced in the Kingdom of Saudi Arabia from consumer goods.
•    Quantity:
The output produced during the target month, measured in specific units (tons, kilograms, cubic meters, etc.)
•    Price:
It is the price of the good or service.

Statistical unit

The statistical unit used in the Construction Cost Index is the establishment.

Statistical population

The statistical population of the Construction Cost Index consists of all contracting offices, engineering offices, and large and medium construction material stores in Saudi Arabia.

Reference area

The Construction Cost Index covers all 13 administrative regions in Saudi Arabia.

Time coverage

Data are available from 2024 to the current month of 2025.

Base period

The base year used for calculating the Construction Cost Index is 2023.

Unit of measure

The results are calculated as a percentage (%) of the annual and monthly change in the general Construction Cost Index, as well as the annual and monthly change in the indices of sub-economic activities (after calculating the indices of economic activities).

Reference period

References period to the variables or dataset as following:
the Construction Cost Index data is based on the previous month for the period of its implementation.

Confidentiality 

Confidentiality - policy

According to the Royal Decree No. 23 dated 07-12-1397, data must always be kept confidential and must be used by GASTAT only for statistical purposes.
Therefore, the data are protected in the data servers of the Authority.

Confidentiality - data treatment

Data of SMEs survey are presented in right tables in order to summarize, understand, as well as extract their results. Moreover, to compare them with other data, and to obtain statistical significance about the selected study population. However, referring to such data indicated in tables is much easier than going back to check the original questionnaire that may include some data like names and addresses of individuals, and names of data providers, which violates data confidentiality of statistical data.
“Anonymity of data” is one of the most important procedures. To keep data confidential,
GASTAT removed information on individual persons, households, or business entities such a way that the respondent cannot be identified either directly such as: (Names, addresses, contact numbers, or identification numbers. etc.) or indirectly (by combining different - especially rare - characteristics of respondents: (age, occupation, education etc.).

Release policy

Release calendar

The publication dates of the monthly releases of the Construction Cost Index are announced through the statistical calendar on the GASTAT website.

Release calendar access

The release calendar is available at: : https://www.stats.gov.sa/statistical-calendar-releases

User access

One of GASTAT’s objectives is to better meet its clients' needs, so it immediately provides them with the publication's results once the Construction Cost Index publication is published.
It also receives questions and inquiries of the clients about the Publication and its results through various communication channels, such as:
•    GASTAT official website:  www.stats.gov.sa
•    GASTAT official e-mail address:  info@stats.gov.sa
•    Client support e-mail:  info@stats.gov.sa
•    Official visits to GASTAT’s official head office in Riyadh or one of its branches in Saudi Arabia.
•    Official letters.
•    Statistical telephone: (199009).

Frequency of dissemination

Monthly.

Accessibility and clarity

News release

The announcements of each publication are available on release calendar as mentioned in 7.2. Release calendar access. The news release can be viewed on the website of GASTAT through the following link: https://www.stats.gov.sa/en/news

Publications

GASTAT issues publications and reports on the Construction Cost Index on a regular basis within a pre-prepared dissemination plan and are published on GASTAT’s website. GASTAT is keen to publish its publications in a way that serves all users of different types, including publications in different formats that contain (publication tables, data graphs, indicators, metadata, methodology, and questionnaires) in both English and Arabic.
The results of the Construction Cost Index are available at:
https://www.stats.gov.sa/statistics 

On-line database

Not available.

Micro-data access 

Microdata are unit-level data obtained from sample surveys, censuses, and administrative systems. They provide information about characteristics of individuals or entities such as: households, business enterprises, facilities, farms, or even geographical areas such as: villages or towns. 
The different types of microdata files to meet different information needs:
•    Public use: 
It consists of sets of records containing information on individuals, households, or business entities anonymized in such a way that the respondent cannot be identified either directly such as: (name, address, contact number, identity number etc.) or indirectly (by combining different - especially rare - characteristics of respondents) such as: (age, occupation, education etc.).
•    Scientific use: 
These files established based on specific methodology asked by data requester to extract the datasets with specific characteristics used for strategic studies and decision making as well scientific research purposes on individuals, households and enterprises with no direct identifiers, which have been subject to control methods to protect confidentiality.
Eligible users can access microdata sets through secure interface built-in by GASTAT called “Etaha” with specific documentary requirements.

Other

Not available.

Documentation on methodology

The framework of the Construction Cost Index:
Concepts, definitions, issues and classifications are based on Eurostat).
Methodology for The Construction Cost Index

Quality documentation

Quality documentation covers documentation on methods and standards for assessing, measuring, and monitoring the quality of statistical process and output. It is based on standard quality criteria such as relevance, accuracy and reliability, timeliness and punctuality, accessibility and clarity, comparability, and coherence.

Quality management

Quality assurance

GASTAT declares that it considers the following principles: impartiality, user orientated, quality of processes and output, effectiveness of statistical processes, reducing the workload for respondents. 
Quality controls and validation of data are actions carried out throughout the process in different stages such as the data input and data collection and other final controls.

Quality assessment

GASTAT performs all statistical activities according to a national model (Generic Statistical Business Process Model – GSBPM). According to the GSBPM, the final phase of statistical activities is overall evaluation using information gathered in each phase or sub-process. This information is used to prepare the evaluation report which outlines all the quality issues related to the specific statistical activity and serves as input for improvement actions.

Relevance 

User needs 

Internal users in the GASTAT for the Construction Cost Index data:
•    National accounts.
Some several external users and beneficiaries greatly benefit from the Construction Cost Index data, including:
•    Government entities.
•    Regional and international organizations.
•    Research institutions.
•    Media.
•    Individuals.
The disseminated key variables used by external users:
The publication is made according to the International Standard Industrial Classification of Economic Activities (ISIC) and the Central Product Classification (CPC).
•    At the level of ISIC economic activity classification: 
-   General construction of residential buildings. 
-  General construction of non-residential buildings.
•    At the product classification level (CPC2):
-  The general index.
-  The index for basic materials.
-  The labor index.
-  The machinery and equipment rental index.
-  The energy index.

User satisfaction

Not available.

Completeness 

The data for the Construction Cost Index is based on a (field) survey conducted monthly by the General Authority for Statistics. It falls under the classification of (economic statistics) and is carried out on a sample of contracting offices, engineering offices, and construction material stores operating in the targeted economic activities, with the data being complete.

Accuracy and reliability 

Overall accuracy

•    The data collected is improved through the researchers, that have been selected according to a set of practical and objective criteria and training program related to the field of work.
•    Alert, prevention, and correction rules are applied during the data collection process on the electronic questionnaire for the Construction Cost Index Survey to improve data quality.
•    Data is checked with previous years to identify any significant changes in the data.
•    The internal consistency of the data is checked before it is finalized.
•    The links between variables are checked and coherence between different data series is confirmed.

Timeliness and punctuality 

Timeliness 

GASTAT uses the Special Data Dissemination Standard (SDDS) issued by the International Monetary Fund. According to this Standard, all statistics agencies are required to publish data on a monthly basis, and with a delay of no more than 6 weeks (42 days) after the end of the reference period. If the data are from different source, they may be published in a different frequency.

Punctuality

Publication takes place in accordance with published release dates for 
the Construction Cost Index in GASTAT webpage.
The data are available at the expected time, as scheduled in the statistical release calendar, If the publication is delayed, reasons shall be provided.

Coherence and comparability

Comparability - geographical

The data is geographically comparable.

Comparability - over time 

The survey started in 2024 as a monthly survey. Below are the main changes that have occurred to the survey: 
•    Compare on an annual basis, comparing the target month and the corresponding month of the previous year.
•    Compare on a monthly basis by comparing the target month to the previous month.

Coherence- cross domain

Not applicable.

Coherence - sub annual and annual statistics 

Not applicable.

Coherence- National Accounts

The data for the Construction Cost Index is consistent with national accounts. 

Coherence - internal

the Construction Cost Index estimates for the reference period have full internal coherence, as they are all based on the same corpus of microdata, and they are calculated using the same estimation methods.

Used Resources

Data revision

Data revision - policy

Collected data for the general index of industrial production is reviewed and its integrity is verified as well. Further, other processes are done, including carrying out calculations, extracting preliminary results, uploading outputs to be stored on the database, and reviewing results for publication.

data revision- practice

Construction cost data for the previous three months can be revised if more accurate data becomes available. If missing data is estimated and updated historical data is received after the results are published, the index results will be revised based on the updated information. (Maximum review is three months.)

Statistical processing

Source data

The main source of data is the construction cost index survey.
The main published variables of the Construction Cost Index data are:
•    At the level of ISIC economic activity classification: 
-  The general construction cost index.
-  The index for building construction activity – general construction of residential buildings.
-   The index for building construction activity – general construction of non-residential buildings.
-   The index for specialized construction activities.

Frequency of data collection

 Monthly.

Data collection

Survey data collection:
The Construction Cost Index data is collected through computer-assisted Personal Interviews (CAPI). 

Data validation

Data are reviewed and matched to ensure their accuracy and precision in a way that suits their nature with the aim of giving the presented statistics quality and accuracy. 
The data of the current year publication are compared with the data of the previous year to ensure their integrity and consistency in preparation for processing data and extracting and reviewing results.
In addition to processing and categorizing the data to verify its accuracy, all outputs are stored and uploaded to the database after being calculated by the General Authority for Statistics. These are then reviewed and processed by specialists in price statistics using modern technologies and software designed for this purpose.

Data compilation

Data Coding:
In the Construction Cost Index survey, statisticians collect a sample of items from respondents based on the activity of the establishment. 
Data editing:
Specialists of the Prices Statistics Department have processed and analyzed data in this stage, and this step was based on the following measures:
Extrapolation and weighting: 
After processing the data collected from the responding establishments, weights for the survey items were created to produce the index tables.
Applied statistical estimation:
GASTAT has relied on formulas approved by international standards to calculate the key indicators of the Construction Cost Index, as follows:
•    Geometric Laspeyres Formula:
 

Adjustment

Not applicable, only final results will be published.