Ameren Assessment Tests, Hiring Process & Interviews Online Preparation – 2025

What Is Ameren?

Ameren is a St. Louis based power company that provides electric and natural gas services to Central and Eastern Missouri, and southern Illinois. It has 2.4 million electric customers and almost 1 million natural gas customers. Ameren is a holding company for Ameren Missouri, Ameren Illinois, Ameren Transmission Company, and Ameren Services.

In addition to careers for workers with experience in the power industry, Ameren has apprenticeship opportunities for those who want to start a career in the trades. There are internships and co-op opportunities available for those on a degree-seeking path. Ameren encourages National Guard, Reservists, and military veterans to apply to see how their military experience can translate to a civilian job. Ameren job categories include corporate services, customer care, digital careers, engineering, energy delivery, and generation. There are many job titles under each of these categories, with opportunities for professionals from various backgrounds.

Ameren’s benefits encourage a healthy work-life balance and include:

• Medical, dental, and vision coverage
• Health savings accounts
• Pension plans and 401k
• Employee assistance programs
• Growth and development opportunities
• Plug in electric vehicle incentives

What Is Ameren’s Recruitment Process?

To get started create a Workday candidate profile on the Ameren website. This profile allows you to apply and sign up for job alerts. If there is more than one position that you are qualified for and have an interest in, you can apply for multiple positions at once.

If your application sparks interest, you will be connected either by email or phone call about the next steps. For some jobs, this means you will be required to sit for pre-hire assessments. Other positions will go straight to the interview stage.

Your first interview is usually a phone interview. This is a brief call to review your application and find out if you are still interested in the job. This will be followed by in-person interviews. These are behavior-based interviews performed by a panel of Ameren hiring leaders.

If you have successfully made it through the testing and interviews you will be given a conditional job offer. Before you are given a start date you will need to complete background checks and for some positions a physical. Once these are completed you will officially be hired.

Ameren’s Pre-Hire Psychometric Tests

Some positions at Ameren require testing to make sure that candidates have the skills in place to quickly and effectively learn the details of their job. The majority of the tests are provided by EEI, the Edison Electric Institute, and are made specifically to evaluate the skills needed to work in energy industry jobs.

• CAST-R – The Construction and Skilled Trades Test-Revised is given to those working in fields like Meter service and repair, electrical repair, and machining and vehicle repair. You will need to demonstrate that you can understand written material, use a diagram to solve math problems, and have a basic understanding of machinery. There will also be a behavioral inventory that will help generate a profile of your work style and ethic. Each test in the battery is multiple-choice and has a time limit. The entire battery takes around 2 hours to complete. The tests included in this battery include Reading for Comprehension (32 questions, 30-minute time limit), Graphic Arithmetic (16 questions, 30-minute time limit), Mechanical Concepts (44 questions, 20-minute time limit), and the Work Preferences Inventory (105 questions, 30-minute time-limit).
• CSR – The Customer Service Representative battery is for call-center and service center employees who need to demonstrate appropriate skills when working with the public. You will need to demonstrate basic skills when working with the systems and handling billing, and an ability to work well with a “live” customer while performing the tasks needed to answer their questions. This battery of tests takes around 4 hours to complete. There are two tests on this battery. The Job Skills Test has 3 sections. Basic Work Station where you will need to show speed and accuracy in data entry, Customer Order which also focuses on data entry, and Bill Inquiry where you will need to show that you can handle a customer’s questions about their energy bills. The second test is the Interactive Test. This is a workplace simulation where you will be handling a customer “call” while correctly entering data and professionally handling the customer questions.
• MASS – The Power Plant Maintenance Selection System Test Battery is for those who be working in maintenance jobs in nuclear, hydroelectric, and fossil power plants. You will need to show that you can understand written directions, can work with machines, can perform arithmetic, and have spatial awareness. All the tests in the battery are multiple-choice and the entire test battery takes around 2 hours to complete. The battery is made up of Reading Comprehension, (36 questions 30-minute time limit),  Mechanical Aptitude (44 questions, 20-minute time limit), Assembling Objects (20 questions, 15-minute time limit), and Mathematical Ability (18 questions, 7-minute time limit).
• MRAB – The Meter Reader Aptitude Battery is a two-test battery. The tests on the MRAB are Using Tables (86 questions, 6-minute time limit) and Coding where you will need to show that you can work with a coding scheme when entering data (72 questions, 5-minute time limit).
• POSS – The Plant Operator Selection System is very similar to the MASS test. It measures the necessary aptitude of those working as operators in fossil, hydroelectric, and nuclear plants. The tests included in the POSS battery are timed and multiple choice. The POSS tests are Reading Comprehension (36 questions, 30-minute time limit, Mechanical Concepts (44 questions, 20-minute time limit), Mathematical Usage (46 questions, 17-minute time limit), and Figural Reasoning (20 questions, 10-minute time limit).
• SASS – The Support and Administrative Selective System is for clerical and administrative professionals. The SASS is made up of several test batteries that will assess your skills in areas like typing, filing, and data entry. The first battery of the SASS is the BCAB, the Basic Competency Assessment Battery. The tests on the BCAB are Classifying (12 minutes to classify as many objects as possible), Spelling/Grammar (8 minutes), and Basic Mathematics (5 questions, 18-minute time limit). The second battery is the Basic Keyboarding Skills Battery, BKSB. There is a Basic Data Entry Test you will have 6 minutes in total to quickly and accurately copy information. Next is the Production Typing Test you will have 7 minutes to re-type text. Finally, you will be given the Advanced Competency Assessment Battery. This is one test in 3 sections where you will be simulating entering a purchase order, completing a purchase order, and checking a purchase order for mistakes.
• SO/PD II – The System Operator Power Dispatcher Test Battery is for candidates in various roles in the energy control systems of power plants. You will need to show that you can think critically and problem solve, work well with numbers, and have good multi-tasking abilities. The first test on the SO/PD II battery is Analytic Thinking Skills (23 questions, 45-minute time limit). This test is further divided into Argument where you will need to draw a conclusion from the information you are presented with (7 questions), Problem Solving you will need to use a written passage as well as additional facts that you are given to answer questions (5 questions), and Logic-Based Reasoning where you will need to use a written passage to determine if a statement is true, false, or if there is not enough information to determine. The other tests you will be given are the Mathematical Usage Test (16 questions, 17-minute time limit) and the Reading Comprehension Test (26 questions, 22-minute time limit).
• TECH – This test is reserved for people who have positions that require an associate degree in a technical field. The questions on this battery are multiple-choice, and you will be timed on each test. The tests in this battery include Graphic Problem Solving (16 questions, 15 -minute time limit), Interpreting Diagrams (16 questions, 15-minute time limit), Mechanical Concepts (44 questions, 20-minute time limit), and Reasoning From Rules which tests your logic network troubleshooting ability (15 questions, 15-minute time limit).

How to Prepare for Ameren’s Assessments?

Do not underestimate the importance of studying and mentally preparing yourself to take the pre-hire assessments. You will have plenty of notice prior to testing, so you will be able to study the areas in which you know you could use a refresher and guarantee good test performance.

Ameren has very detailed study brochures available. Use these so you can understand the type of questions each test will have, and so you know which areas you need to spend time studying. There are also practice tests available for most of the tests. Use them to practice working with a time limit, and so you can see which areas you need to work on.

You are allowed to use a calculator on some parts of the test, but you should still work on solving arithmetic in your head. You can do this as easily as using flashcards. Regular reading helps keep your reading comprehension on point, but you can test it by going online and using reading practice materials designed for students. There are apps available that will help you if you need to work on your understanding of mechanical concepts, or you can review any materials you have left over from coursework.