Industry and economic classification systems

Many people who do research on companies and markets use a system like the SIC codes or NAICS codes. Both systems allow you to determine the activities for companies. The SIC code system is the oldest of the two and can be downloaded as a variable for companies in many databases. A company can get assigned one or more SIC codes. Sometimes a primary SIC code is given, which indicates the main activity. In essence, the Standard Industrial Classification (SIC) is a system for classifying industries by a four-digit code. The system was originally developed in the United States in 1937, and it is used by US government agencies to classify industry activities.  Basic information is available on Wikipedia.
If your research covers a long time frame it may be necessary to determine whether changes that occur over time in the SIC system have an effect. Luckily, an older version of the SIC code system is available. The U.S. Department of Labor, Occupational Safety & Health Administration website allows the user to search the 1987 version SIC codes.
A more recent version of the SIC system is available on the SEC website of the Division of Corporation Finance: Standard Industrial Classification (SIC) 2011 Code List.

The SIC system is also used by agencies in other countries. In the United ingdom they have developed their own version of the SIC codes. This United Kingdom Standard Industrial Classification of Economic Activities (UK SIC) is used to classify business establishments and other standard units by the type of economic activity in which they are engaged. The new version of these codes (SIC 2007) was adopted by the UK as from 1st January 2008. Older versions of the UK SIC system are also available online, specifically, the UK Standard Industrial Classifications 2007, 2003, and 1992 versions.

The North American Industry Classification System (NAICS) is the system used by US Federal statistical agencies for classifying businesses for the purpose of collecting, analyzing, and publishing statistical data related to the U.S. business economy. The NAICS system was developed under the auspices of the Office of Management and Budget (OMB), and adopted in 1997 to replace the Standard Industrial Classification (SIC) system. From 2002 the system is increasingly used. Different versions are available through the US Census website.

The NACE-code (Nomenclature générale des Activités économiques) is a code which is largely used in the European Union and its member states use it to classify commercial and non-commercial economic activities. It is mainly developed as a useful instrument when collecting data and publishing economic statistical overviews. Many companies and organizations exhibit a diverse range of activities. Companies only get assigned a single NACE code, however: the code that indicates the primary acrivity which contributes the most to the total added value of a company. The first version of the NACE was created sometime around 1970. The first revision was published in 1990 and was called NACE Rev. 1. The second major revision (NACE Rev. 1.1) took place in 2002. The second revision was intended to synchronize the system with the  “International Standard Industrial Classification of all economic activities” ISIC of the United Nations. The different NACE versions can be found on the Eurostat website. The Dutch national SBI code system (which replaced the original BIK code system) is based on the NACE system.

The International Standard Industrial Classification of all economic activities, abbreviated as ISIC, is a standard used by the United Nations Statistics Division (UNSD). The ISIC is used to classify economic activities so that entities can be classified according to the activity they carry out.
The ISIC classification combines the statistical units according to their character, technology, organisation and financing of production. The ISIC is used widely, both nationally and internationally, in classifying economic activity data in the fields of population, production, employment, gross domestic product and other economic activities. It is a basic tool for studying economic phenomena, fostering international comparability of data and for promoting the development of sound national statistical systems.
The current and older ISIC versions are available on the statistical website of the United Nations.

When you are using a database, always check the help information to find out what version of an industry code system is being used. If a code system is available but no information on what version it is, you should find out by contacting the owner of the database. Some databases collect data but gather only historical (industry code) information from other sources without using their own version of such as system. The SDC Platinum databases have historical SIC and NAICS codes as they were indicated by the sources that Thomson Reuters uses to collect data.

N.B.: In addition to the aforementioned industry codes there are many more code systems that were developed for statistical purposes in specific countries. The database Amadeus has an easy tool in the help section that allows you to translate specific codes to other codes. This tool is available in the Bureau Van Dijk version of Amadeus:


Datasets in Quandl

Quandl is a new portal that has indexed millions of numerical datasets on the Internet. More information on the background and features is available through their FAQ pages. When you click on a particular dataset listed in the Quandl index, Quandl goes to the original source of that data, extracts the most recent version of that data, cleans it up, and gives it to you in the format of your choice.
Specific topic pages were created on Markets, Economics, Demography & Society.

A big thank you goes to Prof. dr. André Lucas who pointed out the Quandl portal to me.


Specific CBS websites

The Dutch national statistics bureau CBS (Centraal Bureau voor de statistiek) has a general website through which current statistics are made available. In addition two specific websites are available with historical time series data:

1) Dutch census website
The 1795-1971 Dutch Censuses website enables you to view or download most of the Dutch census tables, published in the period 1795-1971. Besides, most of the instructions and attachments (see documentation) are online available. The original records were scanned and digitized and are now available as images as well as MS Excel tables. Many of the original census documents are available in Adobe PDF format.

2) Historical publications website
The CBS bureau is currently digitizing its older historical publications. These are made available through a specific historical” website. Through the website more statistics publications from the 19th and 20th century will become available. Currently the digitized publications include the Statistics yearbook of the Netherlands from 1969-2006 and several older statistics publication series on trade.