EMT Program – EMT Training
Anyone interested in beginning a career as an Emergency Medical Technician will need to enter an EMT program. There are many different Emergency Medical Technician programs you can enroll in, including accelerated programs which can be completed in only a few weeks. I completed my EMT program by attending Community College, but EMT courses can also be completed through technical institutes, online/hybrid courses and other special programs.
The term EMT stands for Emergency Medical Technician. An EMT definition can include many things but in general, it is a medical professional who is trained and certified to provide basic life support (BLS), which includes Cardiopulmonary Resuscitation (CPR), before and during transport to a facility.
For example, the Emergency Medical Technician is capable of providing immediate medical care to a patient after a car accident, while transporting the patient to a hospital in order to provide them with a higher level of care. There are different levels of EMT training which are discussed below.
Any EMT program consists of both classroom curriculum and laboratory skills requirements that students must become proficient in. This means even online EMT courses require students to attend classes on-campus at some point for basic emergency skills training.
EMT training requires hands on practice to become familiar with basic life support (BLS) skills. An EMT requirement is to be familiar with emergency medical equipment before needing to use it during a medical crisis to assist patients.
EMT school includes hands on EMT training with emergency medical equipment like bag valve masks, portable suction equipment, nasal cannulas, and cervical collars.
If you’re considering a career as an Emergency Medical Technician, you can feel confident that the schooling will prepare you with the skills and knowledge you need to confidently work as an EMT.
There are three different levels of EMT certification and they each have their own EMT training program with specific requirements.
Some states have expanded the Emergency Medical Technician scope of practice with an added Critical Care Paramedic Program which trains paramedics and is often used by flight ambulances.
– EMT (EMT B)
– Advanced (AEMT)
– Paramedic (EMTP)
These certification levels can be confusing so they will be discussed more in detail with an explanation of the best place to start EMT training in order to become an Emergency Medical Technician.
Below you will find an overview of the requirements for each EMT Program along with information about them. (EMT pay information can be found on our EMT Salary page.)
Quick Tip: Are you just beginning a career and don’t know where to start? Begin by looking into Basic EMT Training to become an EMT B. This allows you to get certified and work on ambulances or any other jobs an EMT B is qualified for.
Emergency Medical Technicians provide an important role in health care services by creating a critical link between the health care system and emergency scenes.
They are often a patient’s first step into the emergency medical services (EMS) system, and must be able to assess patients on scene and began providing emergent care in the field. Patients experiencing a medical crisis look to these first responders for assistance during challenging pre-hospital situations.
Patients are often in need of critical and emergency care and the Emergency Medical Technician on scene must have the knowledge and skills to determine the most effective pre-hospital care.
Whether a patient is stable or in need of emergency care, the Emergency Medical Technician will assess, treat and safely transport patients to the next level of care in the EMS system.
These professionals should be able to communicate well to other members of the healthcare team and need to give a verbal report whenever transporting or transferring a patient within the EMS system.
One thing that makes working as an EMT challenging and exciting is that interventions for life threatening emergencies must be done with the limited and basic equipment found on the ambulance.
How do you learn the basic life support (BLS) skills and knowledge base needed to perform well as an Emergency Medical Technician?
It may sound intimidating, but the EMT curriculum is easy to learn and the laboratory skills for an EMT B are limited in scope, which means you can be learn them and become proficient in a short time.
Certification is done on a state by state basis, but EMT standards are governed at the National level. There is detailed information about certification on our EMT Certification page.
The National Registry of Emergency Medical Technicians (NREMT) is a great resource for anyone looking for state EMT requirements.
Requirements for EMT Program
Many of these EMT requirements don’t need to be completed until after you are enrolled in the EMT course and attend about 8 weeks of an EMT B course.
They will need to be done before students can begin ambulance ride-alongs or hospital clinical experiences. The list can be intimidating for anyone with financial limitations – don’t get discouraged!
• Candidate must be 18 years of age or older.
• Candidate must have a valid drivers license.
• Applicant must have a current Cardiopulmonary Resuscitation (CPR) Card, the CPR Certification must be for Basic Life Support (BLS) for a healthcare provider. It can be from a healthcare provider in your state. I got my CPR-BLS “Healthcare Provider” card at my local Red Cross Office on a Saturday afternoon.
• A FBI and DOJ Background Check will be done at some point in the certification process. (This probably won’t be done until after you complete your EMT program and apply for certification.) The background check may vary by state. For example, California EMT certification uses Live Scan fingerprinting for the background check which costs the student about $65 total. (Fees to process information: DOJ charges $32, FBI charges $20, Live Scan charges between $10-$20).
• Applicant should have a High school diploma or GED in most states.
• Candidate needs to be physically fit and should be able to lift around 125 pounds – FYI this means lifting patients on backboards, stretchers, etc. and using the correct technique improves your ability to lift and the amount of weight you can lift. For example you will be able lift a heavier patient by lifting with your legs and the stretcher locks so you can lift in stages.
Don’t be discouraged if you are short, a female, or not a muscular person! If you can kneel, reach, crouch, bend, etc. and you are willing to practice lifting technique – you can easily become a great EMT.
I was frequently partnered with another female on the ambulance and we were both under 5’6” tall and each weighed less than 150 pounds. We were always able to transport our patients safely and you can too.
• Applicant should be able to write patient care reports and read and interpret all required documentation. (You will learn about medical terminology and physiology in your EMT program.)
• At some point before being exposed to real life patients, the student will need to show proof that certain vaccinations are up to date.
This can usually be done by showing written proof of childhood vaccinations. I was able to use a very small blue book from my childhood. My mom wrote the vaccine names on the left side and there was an official looking stamp on the right side from the doctor. However, I was missing my last MMR vaccine injection in the book so that vaccine was incomplete.
What do you do if you have no paperwork or aren’t sure about your vaccine status? They also accept titers (you get blood drawn and it’s tested to see if your still immune to the diseases). If you are still immune you just bring this paperwork as proof and your done.
If your immunity has expired (like mine did) you will need to get vaccinated. Also, if you don’t have health insurance you can pay one time fees, or there are a couple of options discussed below for getting temporary insurance to help you meet these EMT program requirements.
What vaccinations must be up to date?
→ Td/Tdap (Tetanus, Diphtheria, Pertussis)
→ MMR (Measles, Mumps, Rubella)
→ Varicella (Chicken Pox) – Or A documented history of Chicken pox.
→ Hepatitis B and Influenza (new each year)
Some EMT schools may allow a student to decline the Hep B and Influenza vaccines.
• Now we get to a requirement many sites don’t mention. Most EMT programs require proof of Health Insurance after enrollment, before you can have contact with patients. This is because you are exposed to dangerous situations and risks of disease during the ambulance and hospital clinical experiences.
If you have health insurance this is no big deal, but for anyone who is uninsured this can seem like a huge obstacle. However, there are some great options to get low-cost health insurance (which will help you meet the vaccination requirements above too) and stay on the path to becoming an EMT.
First, an EMT program may offer their students low-cost solutions to get temporary health insurance while enrolled in their courses.
Second, attending EMT school at a community college is a great way to get your EMT training with the support provided by a college campus.
This is how I was able to become and Emergency Medical Technician even though I was struggling financially. It’s a bit slower paced, but it’s a good option for anyone who has less money and more time.
Many community colleges offer Student Health Insurance at heavily discounted rates or can help students apply for the most affordable health insurance available to them.
Another option is to apply for financial aid at the community college and put that money towards your temporary health insurance costs. You should still be able to work full-time if you attend EMT school at a community college which makes this a good option.
Once you decide on a college, a financial aid councilor will be able to walk you through the process of applying for state and federal financial aid. Another option for financial assistance is grants or scholarships, which is discussed more below.
All of the community college benefits are also available at state schools and Universities, except at a higher cost. However, if you are currently attending college check and see if your school offers an Emergency Medical Technician class. If so, this is a great way to get your EMT-B career started.
EMT Training (EMT-B)
How long does it take to become an EMT? EMT training varies by state and locality. This means that every state has different EMT program courses which are all based on the National Highway Traffic Safety Administration (NHTSA) curriculum.
The NHTSA does require that every EMT program presents a 110 hour EMT training program that contains specific required information. However, this leaves a lot flexibility for states.
For example, California schools require every approved EMT program to include at least 170 hours of training which is much longer than the national requirements.
These EMT training hours will include 146 Academic and Skill hours and 24 hours of Clinical Training (The EMT program will usually require 12 hours of Hospital Clinical Experience and 12 hours of Ambulance Ride Along Experience).
Now that you know how long the EMT training curriculum is, let’s ask the question how long is EMT school? EMT-B school can vary in length depending on the type of EMT program you choose.
There are few different types of Emergency Medical Technician Basic courses available:
Public EMT Schools
This category of Emergency Medical Technician school can include community colleges, state schools, and public University programs and has many benefits for anyone interested in a career in emergency services.
One advantage is that public schools are non-profit organizations and any class units you take at these schools will qualify for transfer to other public schools. This means you can apply your Emergency Medical Service (EMS) credits towards an Associates or Bachelor’s Degree later on.
Another big advantage of these EMT schools is that you pay per unit rather getting charged a set rate for the EMT program as a whole.
The program I went through to get my EMT training was at Orange Coast Community College (OCC) in California so I will use that as my example. OCC offers their EMT-B program under the Emergency Medical Services heading.
It’s easy to tell this is the correct class schedule for an Emergency Medical Technician Basic (EMT-B) because the class description states:
“completion of the EMS course qualifies the student to sit for the National Registry of Emergency Medical Technicians’ certifying examination, and therefore obtain EMS certification in any California County.”
A EMT training program that qualifies you to sit for the NREMT exam is what you’re looking for to become certified as an Emergency Medical Technician in your state.
The required classes for the OCC program total 12 units and are listed as:
– Emergency Medical Services EMS which is a 10 unit class
– Emergency Medical Services lab EMS which is a 1 unit class
– EMS Clinical Internship EMS which is a 1 unit class
There are also a couple recommended classes to help students succeed, but these are not required. They are:
– Medical Terminology which is a 3 unit class
– Anatomy-Physiology which is a 4 unit class
– Interpersonal Communication which is a 3 unit class
(I think the Medical Terminology class is a great class to take, but the Anatomy Physiology class gets more in-depth than is needed for a Basic Emergency Medical Technician: EMT-B.)
Each unit at a community college in California costs $46 (this varies by state) which is a total cost of $552 for the 12 required units or $1012 if you choose to take all three of the recommended classes. These units make up the majority of your EMT education cost.
This is good news because a great thing about public schools is they offer Financial Aid for anyone who qualifies.
In California the cost of each unit can be removed for anyone who qualifies for the BOG Fee Waiver which is income based and takes family size into consideration. The Fee Waiver requires you maintain good grades to stay eligible, but it removes the majority of costs related to EMT school.
Financial aid benefits are different for each state, but you can apply for both federal (FAFSA) and state financial aid.
Once you decide which school you’d like to go to you can go to their financial aid office and talk to a financial aid councilor who will walk you through which programs to apply for.
There is no penalty for applying for aid, so if finances are a struggle I recommend going to the Federal student aid site (FAFSA) and filling out an application if you’re enrolling in an EMT school.
There are also grants and scholarships available as other sources of financial aid, or even a student loan is possible, but those need to be paid back unlike the other sources of financial aid.
I recommend finding financial aid resources through whichever college you decide to attend because there are many financial aid scams online. For example, FAFSA is free to fill out, so anyone charging money to do it is a scam.
A disadvantage of a public EMT program is they tend to take an entire semester to finish and are only offered with each Spring, Fall and Summer semester.
For example, the Spring semester will be a 16 week EMT training program that begins in January and ends in May. If you want a quicker EMT program the Summer semester is usually 10 weeks long going from May to August.
I highly recommend getting your EMT education at a public institution if you need financial help and can qualify for one of the many financial aid opportunities available. This is also a good option if you’re not in a rush and plan to use the units towards an Associates or Bachelors degree later.
I wasn’t planning on it, but my Emergency Medical Services class units were helpful later when I went back to school and joined a Registered Nursing Program.
Private EMT Schools
Private institution schools include many of the for-profit EMT training programs available. This includes the accelerated, online hybrid, and boot camp EMT training programs along with Emergency Medical Technician courses that are set for a normal length and pace.
A for-profit EMT program will usually cost more than a public school EMT program, but often the price includes things like a blood pressure cuff, uniform, or other needed medical equipment.
These Emergency Medical Technician courses also tend to come with added convenience and support to help guide the student, who is also a customer. A private school EMT-B course also tends to offer more flexibility in scheduling than a public institution.
For example, a private course in New York can cost around $1250 for the complete EMT program which can vary from around 3-6 months in length depending on which days and hours you want to attend classes.
Often private schools will offer many scheduling options including twice a week, daytime, evenings or even weekend classes.
These regular, non accelerated programs are not high intensity and usually don’t require all day classes so they are good for anyone who wants to get their EMT license at a slow pace with time to practice basic skills.
They are also great options for anyone who will be working full-time while getting their EMT education and want more class options than public courses provide.
Another benefit often included with the added cost of private EMT schools is they often offer help with preparing for the National Registry of Emergency Medical Technician (NREMT) Exam.
Online EMT Course
EMT training online is different from other studies because of the hands on nature of emergency medical skill teaching. For this reason online EMT classes are offered as hybrid programs with both an online component and mandatory classroom time.
Frequently the student is required to finish the online portion of the program before they can begin to participate in the classroom skills portion.
The online curriculum allows students to learn academic lesson plans with flexibility, but requires self-discipline. Online Emergency Medical Technician Basic programs tend to cost less than an accelerated program, but more than a public EMT program.
Like all of the private EMT courses price will vary depending on your state and locality but they tend to cost around $900 in California and around $1200 in Texas.
I don’t know how effective this teaching method is as an EMT program, but it probably requires a highly motivated student to complete all the at-home coursework.
My experience with online classes is that it becomes very tempting to just do what’s required to pass with a good grade. EMT training teaches how to assess a patient on scene quickly and accurately while using critical thinking to determine the best course of treatment.
These prehospital skills are very important and learning the fundamentals will determine your assessment abilities when working on the ambulance later. It is very important to learn these skills early in school so you can improve on them throughout your EMT training.
For these reasons, I’d only recommend the online EMT courses under certain circumstances. EMT classes online can be great for people with prior healthcare experience or knowledge.
They may also be a good option for individuals who are good at learning without supervision and who can stay self motivated and disciplined.
Accelerated EMT Program
These programs are a convenient way to get all the required Emergency Medical Technician skills and knowledge very quickly. However, they are a more expensive way of getting your EMT studies done.
A nice thing about accelerated programs is the high cost often includes extras like the CPR BLS card and National Registry of Emergency Medical Technician (NREMT) Exam preparation. (You can find information on our National Registry of EMT Exam page.)
You can find accelerated EMT-classes that are offered weekdays or even ones scheduled for full-time workers. Here is an example schedule from an EMT accelerated program in California.
The EMT-B class begins September 14, 2017 and ends November 11, 2017 and the classes are offered on Nights and Weekends. Specifically on Tuesday and Thursday evenings from 5-9pm and on Saturdays from 9-3pm. The overall cost of the course is around $1300 and there is a payment plan available.
As you can see this is a great schedule for anyone needing to attend school while working full-time. If your interested in getting more information about the program above check it out here.
Accelerated EMT programs can be found in many states and are a good way to get licensed quickly if your able to learn fast and finances aren’t an issue.
EMT Boot Camp
EMT boot camps are basically a super accelerated school for the Emergency Medical Technician – EMT B. This education style is not for everybody because involves long hours in the classroom and is a more expensive way of getting certification. An EMT boot camp will often advertise with headlines answering the question how long is EMT school such as “Become an EMT in 18 days” or “EMT 14-Day Boot Camp.”
These programs are fast paced and usually involve 8-12 hour days spent learning classroom and clinical skill. For example, the 18 day boot camp program above is from a school in Massachusetts and requires students meet Monday through Friday from 9-5pm.
Like other accelerated EMT programs, the boot camps often have extras included in the price such as CPR BLS Certification for healthcare providers and assistance to help students successfully pass the National NREMT exam.
The cost for the Massachusetts-based EMT boot camp varies from $1400 – $2000 depending on the dates you choose, and if you don’t live near the campus locations there will be additional costs for accommodations.
They do offer payment plans and financing to help cover costs. If you want more information about this EMT program check it out here.
Overall, EMT boot camps are a good option for anyone who wants to get licensed very quickly, is willing to travel, wants guarantees from their education program to pass the NREMT exam, and don’t mind spending extra money.
Free EMT School
I have not been able to find legitimate Emergency Technician Programs that are free. Also I have spoken to anyone who attended a free school and was working as an Emergency Medical Technician.
The only exceptions I have seen are occasion small local classes offered that waive the fees for Military Veterans.
Most of the websites claiming to be free EMT education programs have been misleading headlines that actually led to pay programs once I clicked into their sites. If you’re wondering why people do this, it’s a type of Clickbait (online term) combined with the old Bait and Switch (offline term).
I don’t recommend doing business with anyone who uses deceitful tactics like this to trick people into clicking on their link.
I definitely would not want to give my credit card information to anyone who uses manipulative tactics like promising free classes when they know there are no free classes available.
I recommend sticking with businesses who are honest and straightforward with what they offer and what it costs.
Advanced EMT Training AEMT/EMTI
Emergency Medical Technician Intermediate (EMTI) has slowly been transitioning in the role of AEMT since 2013. Therefore, depending on your state this level of training may be referred to by either title. I will be using AEMT since many states have changed over to this already.
Let’s start by answering the question: What is an AEMT?
An Advanced Emergency Medical Technician is a mid-level Emergency Medical Services (EMS) provider, which means they are a level above EMT-B and a level below a Paramedic (EMTP) in training. An AEMT is trained to do many of the same skills the EMTI is able to do.
These will vary based on state regulations, but in general the skills of an AEMT includes the initiation of peripheral intravenous (IV) therapy, administration of specific intravenous (IV) fluids, the administration of epinephrine, basic airway management, supraglottic airway insertion, and the administration of certain medications like nalaxone (Narcan), glucagons, Nitrous Oxide, and Albuterol.
These are called limited Advanced Life Support (ALS) skills and you will continue to expand on them in Paramedic school.
There are a couple of options professional Emergency Medical Technicians have when it comes to advancing their career level. It’s possible to skip the basic level and train for the Advanced level directly, or you can become an EMT-B and then go back to school to become an AEMT at a later date.
Before making this decision it’s important to know that not all areas use AEMT’s, so make sure you are familiar with the practices of your state before starting your education.
For example, according to emsa.ca.gov California mostly uses Advanced Emergency Medical Technicians in areas that are rural or sparsely populated, and there are about 100 AEMT’s certified through local EMS agencies.
Training hours required for a candidate who is already a certified Emergency Medical Technician (EMT-B) include a total of 160 hours. Eighty of the hours are didactic (academic) and skills, 40 are clinical training, and 40 are field internship.
This is quite a bit of extra emergency medical education, so you want to make sure your area will hire and pay an AEMT salary.
EMT training is available in all the same EMT-B program formats discussed above. The program costs are likely to be more expensive than the EMT-B training if you are starting your Emergency Medical Services (EMS) education and going straight to AEMT.
However, if you are already a certified Emergency Medical Technician the schooling should be about the same costs as EMT-B school. For example, Lenoir Community College in North Carolina offers a 16 week EMT-B to AEMT/EMTI course which is an online hybrid format.
The tuition is $180 but after textbooks and other costs such as uniform and EMS testing, the class ends up costing around $550 total.
After completing an EMT training program, candidate must pass the National Registry of Emergency Medical Technicians (NREMT) exam for AEMT in order to obtain certification.
Paramedic Training (EMTP)
Paramedics are trained and licensed in Advanced Life Support (ALS) which is more invasive and comprehensive than Basic Life Support (BLS). Paramedics (EMTP) have an expanded scope of practice than the EMT-B and AEMT/EMTI which leads to a higher salary and more extensive job opportunities.
Paramedics have job opportunities with Fire Departments and Emergency Medical Services (EMS) all over, providing ALS pre-hospital care to patients in need.
In addition to the Advanced Emergency Medical Technician skills, paramedics can administer at least 25 medications, perform endotracheal and nasogastric intubation, utilize and monitor electrocardiographic devices, perform a needle thoracostomy in addition to many other pre-hospital skills.
Paramedics are an integral part of the Emergency Response System (EMS) and provide advanced interventions in a pre-hospital care setting and during transport of patients.
For information about the new paramedic schooling requirements and testing changes, see our Paramedic Page page.
Many Paramedic schools require an EMT-B certification as a prerequisite and some also have specific experience requirements.
For example, Saddleback College requires one year of full-time work as an EMT on an emergency response vehicle such as a private ambulance or fire truck in order to qualify for their program.
Mt. San Antonio College (Mt. SAC) is another well-known Paramedic program in the area and it requires 1200 hours of field experience to be completed before a candidate can apply for the program. For more information check out our EMT Training Courses page.
Because of these requirements many emergency medical responders begin their career as an EMT-B and work for a year or so to get the needed experience to apply for paramedic school.
That was the path I chose. After working on an ambulance and getting 1200 hours of field experience, I applied for Mt. SAC and went to the campus for the written testing. After passing the tests one of the instructors mentioned that I should go into Nursing because I enjoy emergency care so much.
I had never even considered a career in Nursing because in my mind I saw nurses as only doing what doctors instructed without much independence or autonomy.
The paramedic instructor, who also worked as an RN, told me how nursing really is and changed my career path. So no matter what path you take, getting a year of experience as an EMT won’t be a waste.
My experience on the ambulance made me comfortable with patient assessment and plan of care and it helped with the constantly changing environment of the Intensive Care Unit (ICU). (To find out more about the kind of jobs that a Basic EMT can do, go here.)
There are programs, usually privately owned, that don’t require time in the field as an EMT-B for anyone who wants to skip getting a basic certification and go straight to EMT Paramedic without any other medical experience.
These are sometimes referred to as “zero to hero” programs and can produce successful emergency medical responders even though these professionals initially lack experience as an EMT.
When choosing a paramedic school it’s important to find an accredited program. Starting in 2013 candidates are required to complete their EMT Paramedic education from a program accredited by the Commission on Accreditation of Allied Health Education Programs (CAAHEP).
If a Paramedic school is not properly accredited by CAAHEP, the student will not be able to apply to take the National Registry of Emergency Medical Technician (NREMT) Paramedic Exam and get the Paramedic certification.
National standards set by the National Highway Traffic Safety Administration (NHTSA) for paramedic school programs require accredited programs consist of about 1000-1200 total hours of instruction.
While each state has it’s own specific standards, the paramedic courses must have around 500 hours of academic and skills training, 200 hours of hospital and clinical training, and 300 hours of field internship.
These hours are flexible depending on the size of classes and other similar factors.
The cost of Paramedic programs can vary drastically depending on the type of school. Many of the same schools options present for an EMT-B are available to paramedics. One difference is instead of EMT Boot Camps there are Paramedic Academies (usually for Fire personnel).
I also recommend a public institution, like a community college, to get your EMT Paramedic education for the same reasons they are recommended for EMT-B programs.
These are good programs because you can use your class units towards an Associates, Bachelor, or other degree later. Another reason is the financial aid options available, which could be a big factor because Paramedic school is longer and more expensive than the other EMT training programs.
For an example of how much paramedic school cost I will use Saddleback College in California.
This is a community college so a candidate may qualify for financial aid, and it’s in California which means there is a chance to have the entire tuition fee waived with a BOG Fee Waiver. For more information on this scroll up to Requirements for EMT Programs above.
The main costs for this paramedic course are split into two sections. The first section is Saddleback College Fees:
• Tuition (33.5 units at $46 a unit) is $1,541
• Material Fees $210
• Health Fees for two semesters $38
• Parking fee for two semesters $60
— Total $1849 —
The second section includes Other Costs:
• Books $500
• Insurance $20
• Uniforms $150
• Supplies $150
• State License $250
• Live Scan $51
• National Registry Profile $150
• National Registry Written Exam $180
• National Registry Practical Exam $155
— Total other costs $1606 —
Entire Paramedic Program Costs $3455
This makes the total estimated cost of the entire program $3455 at Saddleback community college before any financial aid. This price will vary by state and program but it’s an investment to advance career training and successfully completing the program will ultimately lead to a higher salary.
Some important things to keep in mind before starting a Paramedic Program:
• This will be a much bigger intrusion in your life than becoming an EMT is. Becoming a paramedic is going to take more time and energy because you will be learning valuable knowledge and skills while increasing your responsibilities.
• Let your loved ones know the commitment you are making to advance your medical career. For 12-18 months paramedic school will be taking over your life. You will be attending classes, doing hours of required reading, skills practice, and attending a lot of clinical hours.
• It’s important to have support from loved ones so your relationships don’t suffer. If you tell friends and family ahead of time that you will not be available because most of your time is going to be spent working and studying, they are more likely to support you and not be resistant to changes.