Methodology and Quality Update

Methodology and Quality last update 

21/05/2025

Statistical Presentation

Data description 

•    Setting of objectives:  
-    Measuring changes in the sale prices of products and services at the level of local producers.
-    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. 
-    Adoption of the National Classification of Economic Activities (ISIC4) and the International Standard Classification of Industrial Activities (ISIC).

•    Calculation of weights:
The weights of economic activities in the Producer Price Index were calculated based on the value added of economic activities for the year 2023, drawing on the results of the Structural Survey conducted by the General Authority for Statistics.
.Collecting the prices: 
-    Collect product prices periodically (monthly) to ensure that the indicator is constantly updated by (telephone - self-completion - field).
-    Using the selling prices provided by local producers at the factory door without tax and transportation.
•    Calculating the index: 
-    Using the digital index formula for producer prices to calculate relative price changes. 
-    Applying the (Laspeyres) formula or the (Fisher) formula to calculate the index.
•    Analysing Data:
Analyzing the collected data to understand price changes, interpret the results, and provide 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

Apply the following classifications in the Producer Price Index (PPI):
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 PPI survey covers the following main economic sectors:
•    Mining and quarrying activity.
•    Manufacturing Industry Activity.
•    Electricity and Gas Supply Activity.
•    Water Supply, Sewerage, Waste Management, and Remediation Activities.
The Producer Price Survey covers all economic sectors.
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 for the Producer Price Survey:
•    Producer price index (PPI):
It is an economic index that reflects the relative changes in the prices of domestic products based on data from the Producer Price Survey. Which is conducted on a sample of industrial establishments operating in the targeted industrial activities, including the mining and quarrying activity, manufacturing activity, and the activity of electricity and gas supply, and Water Supply, Sewerage, Waste Management, and Remediation Activities.
•    Monthly rate of change: 
A rate that reflects the monthly relative changes in producer prices between the current and previous months.
•    Annual rate of change:
An index that reflects the annual relative changes in producer prices 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:
It refers to the outputs produced during the target month, measured in a specific unit of measurement (ton, kilogram, liter, etc.).
•    Price:
It is the commodity's price at the factory gate, excluding tax and transportation costs.

Statistical unit

The statistical unit used in the Producer Price Survey is the establishment.

Statistical population

The statistical population for the Producer Price Survey consists of all industrial establishments in the Kingdom of Saudi Arabia.

Reference area

The survey covers 13 administrative regions in the Kingdom of Saudi Arabia.

Time coverage

Data are available from 2023 to the current month of 2025.

Base period

The base year used to calculate the producer price index is 2023. 

Unit of measure

The results are calculated as a percentage (%), reflecting the annual and monthly change in the general Producer Price Index - The percentage of annual and monthly changes in the indices of sub-economic activities (after calculating the indices for the economic activities).

Reference period

References period to the variables as following:
Producer Price Survey 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 is 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 Producer Price Index (PPI) Survey 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 Producer Price Index (PPI) survey 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
•    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://stats.gov.sa/news

Publications

GASTAT issues Producer Price Index Survey publications and reports regularly within a pre-prepared dissemination plan and is 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, methodology and quality Report, methodology, and questionnaires) in both English and Arabic.
The results of the Producer Price Index Survey are available at:
https://www.stats.gov.sa/statistics

On-line database

Not available.

Micro-data access 

Microdata are unit-level datasets derived from surveys, censuses, and administrative records. These datasets provide detailed insights into individuals, households, businesses, and geographic areas, supporting the development of statistical indicators and in-depth research.
The different types of microdata files to meet different information needs:
•    Public use:
It consists sets of records containing information on individual persons, households, or business entities anonymized in such a way that the respondent cannot be identified either directly (by name, address, contact number, identity number etc.) or indirectly (by combining different - especially rare - characteristics of respondents: 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.
Access to Scientific Use Files (SUF) is restricted to authorized researchers who comply with ethical and confidentiality standards. Representative samples of SUF can be obtained through GASTAT's secure platform, "Etaha," while more sensitive datasets are accessible only through secure physical lab environments managed by GASTAT.

Other

Not available.

Documentation on methodology

Producer Price Index framework:
Concepts, definitions, issues and classifications based on international standards are based on the United Nations Statistical Commission Manual.
Methodology Producer Price 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 Producer Price Index data:
•    National accounts.
Some several external users and beneficiaries greatly benefit from Producer Price Index data, including:
•    Government entities.
•    Regional and international organizations.
•    Research institutions.
•    Media.
•    Individuals.
The disseminated key variables that used by external users:
It is published according to the classification of economic activities (ISIC) :
•    At the level of ISIC economic activity classification: 
-    General Producer Price Index.
-    Index of mining and quarrying activity.
-    Index of manufacturing activity.
-    Index of electricity, gas, steam, and air conditioning supplies.
-    Index of water supply, sewerage, waste management and remediation activities.

User satisfaction

Not available.

Completeness 

The data of the Producer Price Index is based on the field and telephone survey of the index of industrial production, which is a survey conducted by the General Authority for Statistics on a monthly basis and falls under the classification (economic statistics) and is implemented on a sample of industrial establishments that are engaged in the targeted economic activities represented by mining and quarrying activity, and manufacturing activity. electricity and gas supply activity, water supply activity, sanitation activities, waste management, and treatment are in complete condition.

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 Producer Price 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 not 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 Producer Price 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 at the country level, but not at the administrative region level, due to the publication being at the national level in Saudi Arabia.

Comparability - over time 

The survey began in 2023 as a monthly survey. The following are the main changes 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 

Published PPI data is applicable. 

Coherence - internal 

The Producer Price 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.

Resources used 

Data revision

Data revision - policy

The data collected for the PPI calculation was reviewed and validated, calculations were performed, preliminary results were extracted, outputs were uploaded and stored in the database, and then finalized for publication.

Data revision - practice

Producer Price Index data can be reviewed for the previous three months if more accurate data is available, if missing data is estimated and updated historical data is received after the publication of the results, the index results are reviewed based on updated data (maximum review is three months).

Statistical processing

Source data

The main source of data is the Producer Price Survey, a monthly survey where data is collected from a sample of 1,004 establishments.
The main published variables of Producer Price Survey data are:
•    At the level of ISIC economic activity classification: 
-    The General Producer Price Index (PPI).
-    General index for mining and quarrying activity.
-    General index of manufacturing activity.
-    Index of electricity, gas, steam, and air conditioning supplies.
-    Index of water supply, sewerage, waste management and remediation activities.
•    At the level of CPC Central Product Classification:
-    The General Index.
-    Index for ores and minerals; electricity, gas, and water.
-    Index of manufacturing activity.
-    Index for food, beverage, textiles, apparel, and leather products.
-    The index for other transportable goods other than mineral products, machinery, and equipment.
-    Index for metal products, machinery, and equipment.

Frequency of data collection 

Monthly.

Data collection

Data collection from the survey:
Data for the Producer Price Survey is collected through Computer-Assisted Telephone Interviews (CATI), Computer-Assisted Web Interviews (CAWI), and 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 the data processing and tabulation to check their accuracy, all the outputs are stored and uploaded to the database after being calculated by GASTAT to be reviewed and processed by specialists in Research and Development Survey through modern technologies and software designed for this purpose.

Data compilation

Data Coding:
Interviewers in the Producer Price Survey collect from respondents, a detailed description of each field. This information is then coded in-house by an automated process, which is reviewed by a small-dedicated team of coding experts using a series of consistency checks.
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:
•    Sorting and arranging data in groups or different categories in a serial order.
•    Summarizing detailed data into key points or data.
•    Combining many data segments and ensuring their interconnection.
•    Processing incomplete or missing data.
•    Processing illogical data.

•    Converting data into statistically significant data.
•    Arranging, presenting, and interpreting data.
Compensation (for non-response cases or incomplete datasets): 
Missing data is compensated for using the "Producer Price Index Guide" from the International Monetary Fund (IMF).
Extrapolation and weighting: 
After processing the data collected from respondents, survey weights were generated to produce indicator tables by following two main steps in creating survey weights: 
•    Adjustment of non-response.
•    Calibration weight
Applied statistical estimation:
GASTAT has relied on the formulas approved by the international standards in calculating the Producer Price Index key indicators, as follows:
•    Geometric Laspeyres Formula:

Where the details of the equation are defined as follows:
-    I: It is the indicator at each level of classification.
-    t: The period (month).
-    Exponent: Is the weight of the item/total weights for each level.

Adjustment

Not applicable, only final results will be published.