If you have trouble keeping your New Year’s resolutions, you may benefit from taking a more scientific approach.

In the late 1970s, researchers studying the experiences of smokers to learn why some were able to quit on their own and others needed further treatment found that people move through varying degrees of readiness when changing behavior. Initiatives that don’t match the correct stage of change will be ineffective, because the person will not be ready for it.

By identifying where you are in the process and what you can do to reach the next stages, you increase your chances of sticking to your healthy resolutions.

Precontemplation: You’re not ready for a change

If there are things you want to change (such as a poor diet or a sedentary lifestyle), one of your first questions is probably, “How did it get to this point?” Likely it’s because you didn’t see them as a problem at the time. That’s where people in this stage are.

It sometimes takes an epiphany, such as a health scare or a personal issue, to move out of this stage. If you’re reading this, though, you are likely at one of the steps below.

Contemplation: You’re open to the idea of changing, but are not immediately ready to prepare to take action

Change is often slow and difficult. It’s easy to find excuses and justifications that prevent us from moving forward with change. For instance, we tell ourselves that we should get more exercise, but we don’t the time to make it happen right now.

If you’re in this stage, remind yourself of how changing your behavior will benefit your life. Try writing out a list or taking a self-assessment to get off the fence.

Preparation: You’re taking steps to change behavior

Once you decide for sure that you’re going to change, you need to get ready to do it. The more you plan for success, the better your chances will be. This is the stage that usually get the most focus and attention. These are where the diet plans and gym memberships come in.

There are several best practices for this stage. Make SMART goals. Focus on small changes that can have a positive impact. Identify and eliminate barriers that get in the way. And gather support from family and friends.

Action: You’ve implemented your plan

Congratulations! You’ve taken your first step toward the new you. Many people like to choose a specific date and time to begin the action stage. That helps make it a commitment in our minds.

Now you have to keep at it until your actions become behaviors. According to the researchers, the action stage lasts for approximately three months before moving into the final stage.

Maintenance: You’re sticking to the plan and making the change a habit

At this stage, you need to continue to avoid slipups or falling back into bad habits. If you do, you may need to work back up to this stage.

Don’t get discouraged. It’s common for people to have to repeat some of these stages multiple times before finally achieving their goals. Know your temptations, and keep at it until it sticks.