STANDARDIZED OCCUPATION & INDUSTRY CODING

SOIC Frequently Asked Questions

About SOIC

What is SOIC?
The Standardized Occupation and Industry Coding (SOIC) system is a standalone Windows based software package that assigns 3-digit numerical codes to narrative industry and occupation descriptions. Using data that have been imported from existing files or entered directly into SOIC using the data entry screen, the software can code one record at a time or all records in a file. The software assigns codes based on the 1990 Bureau Of the Census Alphabetical Index of Industries and Occupations.

How much does the software cost?
Because SOIC was created in the public domain, the software can be downloaded free of charge.

Where can industry and occupation information be found?
Many data sets contain narrative text for industry and occupation, including:

Vital records systems
Cancer registries
Worker’s compensation systems
Healthcare records

Why collect industry and occupation information?
The collection of industry and occupation (I&O) information serves many purposes:

To associate specific health outcomes (e.g., a particular cancer or cause of death) with certain industries and/or occupations
To identify areas in need of further research
To assess socioeconomic status and identify persons who may be at high-risk of disease or injury.

This type of information can be used by public health workers, industrial organizations, employers, and others to provide the best possible hazard abatement and control, and safety and health programs for workers.

What is the advantage of an automated coding system?
Manually assigning industry and occupation (I&O) codes can often be expensive, time consuming, and not highly consistent. An automated system like SOIC can decrease the number of cases a coder must review and create consistency in a records system.

What types of data are accepted by SOIC?
SOIC offers flexible data access features. A user can:

Enter data directly into SOIC
Operate directly on external data tables in dBase, FoxPro, and Access
Import and export text files

Will the software be updated?
The current version of SOIC assigns codes based on the 1990 Bureau of the Census (BOC) coding scheme. No further revisions will be made to SOIC. However, NIOSH is currently developing new coding software called the NIOSH Industry and Occupational Computerized Coding System (NIOCCS). As SOIC did, the new NIOCCS will have the ability to translate free text industry and occupation narratives found on employment and health records to standardized I&O codes including the 1990 and 2000 Bureau of the Census I&O codes as well as NAICS. For additional information, view the Industry and Occupation Coding Support page.

Coding Results

What is the overall performance of SOIC?
NIOSH conducted a comparison of SOIC and an expert’s manually assigned codes for 48,067 cases from a death certificate based surveillance system. The number of software-assigned codes that matched the expert manual coder is shown below. In this test there was no adjudication of the results; that is, the mismatched cases were not reviewed to determine if the SOIC autocoder or the manual coder was actually correct. These results are provided as an illustration. Coding results will vary and depend upon overall data quality. The software does not perform well on narratives with company names and other ambiguous information.

Industry codes matched	36,376 cases (76%)
Occupation codes matched	36,207 cases (75%)
Both occupation and industry codes matched	30,389 cases (63%)

How well does the software perform on industry narratives?
To identify and categorize SOIC errors, unique industry and occupation narratives were reviewed separately. Using Bureau of the Census industry divisions as a guide, SOIC and manually assigned codes were compared. Of the 48,067 total cases, 16,096 cases contained unique industry narratives (all duplicates were removed, e.g., the file contained the term "construction roofing" in the industry narrative field only once compared to the numerous times it may have appeared in the original file of 48,067 cases). More than half (9,262) were coded correctly. The software incorrectly coded 3,296 narratives and could not code 3,538 narratives. Problems that were identified are characterized below.

Codes were in different division categories but were unrelated (e.g., construction vs. hospital)	1,159 (35%)
Codes were in different division categories but were related (e.g., food manufacturing vs. retail grocery)	1,032 (31%)
Codes were in the same division category	825 (25%)
Codes were in different division categories and one code was an unclassified code	248 (8%)
Codes were in different division categories and one code was a non-worker code	32 (1%)

How well does the software perform on occupation narratives?
To identify and categorize SOIC errors, unique industry and occupation narratives were reviewed separately. Using Bureau of the Census occupation divisions as a guide, SOIC and manually assigned codes were compared. Of the 48,067 total cases, 9,808 cases contained unique occupation narratives (all duplicates were removed, e.g., the file contained the term "carpenter" in the occupation narrative field only once compared to the numerous times it may have appeared in the original file of 48,067 cases). Almost half (4,852) were coded correctly. The software incorrectly coded 2,020 narratives and could not code 2,936 narratives. Problems that were identified are characterized below..

Codes were in different division categories but were unrelated (e.g., nurse vs. machine operator)	789 (39%)
Codes were in the same division category	748 (37%)
Codes were in different division categories but were related (e.g., machine operators vs. operating engineers)	388 (19%)
Codes were in different division categories and one code was an unclassified code	60 (3%)
Codes were in different division categories and one code was a non-worker code	35 (2%)

What are the limitations to using an automated system?
Because of data quality, there are often challenges to using an automated industry and occupation (I&O) coding system.

Multiple ways of reporting industries or occupations
- Industry: Hauling/Transporting/Trucking
- Occupation: Teacher/Tutor/Instructor
State-specific business names
- Industry: Bar Church Key Pub/Harper’s County Ham
Ambiguous I&O narratives
- Industry: Food/Computers
- Occupation: Healthcare/Assistant

What can be done to data to improve the software’s performance?
Data quality plays an integral part in software performance. The cleaner, more straightforward your data, the better the software performs. Several steps can be taken to ensure well-coded data. Before coding, review the industry and occupation (I&O) narratives in your data and modify as needed:

Spell out abbreviated words and acronyms
Example:
- AFB = Air Force Base
- ED = Emergency Department
Use business type instead of business name
Example:
- Construction instead of Smith & Sons Contracting
Make sure that industry and occupation narratives are in appropriate fields
Delete non-essential words
Example:
- a teacher
- works as a lawyer

Should I perform quality control on coded data?
After data have been coded, we strongly encourage performing quality control to ensure that there are no systematic errors.