Want to Know if Your App is Successful? Check These Metrics. With new apps launching every day, an entrepreneur needs to worry more about just downloads to be successful.

Building a mobile app can be a cash cow, but if not developed correctly, it can be among the 78 percent of apps users never return to after using once.

If your app is free, you're solely relying on either advertising or in-app purchases (the freemium model) for monetization, which if no one is making multiple visits, you are not going to be making much revenue.

That said, more mobile startups are offering up free apps in hopes of snagging ad dollars or getting people to make purchases for advanced features, virtual good or more functionality. In fact, at last count, 76 percent of all revenue in the Apple app store in the US and over 90 percent in the Asian markets came from freemium apps or in-app purchases, according to Distimo's report How the Most Successful Apps Monetize Their User Base.

Even Snapchat, a completely free app was offered a staggering $3 billion-dollar buyout by Facebook because of its mind-numbing user engagement numbers (currently about 400 million photos shared per day).

Want to know how your mobile app is measuring up? Check out these metrics:

1. Downloads. While downloads alone can't determine if an app is a winner, they still play a role in measuiring its success.

For the freemium model, the more downloads, the higher the probabilty your app will succeed in converting free users into paid ones. And if the app does cost money to use, the download metric is even a bigger deal.

Make sure you put your download numbers in perspective with the number of active users. Measure how many people download and use the app, and monitor whether the app gains or loses popularity over a certain period of time or during a particular campaign. You can also track the statistics about the devices and platforms your app is used most on.

Third-party tools such as AppFigures and App Annie allow you to link your iTunes account to give you an update on these statistics

2. Engagement. This is what Snapchat and Instagram's valuation was made up of: A cornucopia of highly-engaged users accessing the app at least once daily and in most cases, several times every day. You want your app to emulate this model and have high engagement.

You want consumers to use your app every day, making it an integral part of their daily lives.

While engagement is measured by how frequently users come back to your app, the metrics can vary. Engagement can meaure frequency of opens, duration or usage, number of screens used and conversion rate for events. Depending on your app's goal, these metrics will tell you if your users consider your product indispensable.

3. Retention. You not only want your user base to grow but also want to make sure people are staying. One way to do this is by updates. Every app goes through an evolution -- from its launch to a number of release versions, which may have feature and bug fixes or enhancements. These updates tend to occur after research or user feedback. Make sure you listen to the users, especially the ones that will go the extra mile to install an update for an enhanced experience. Tracking this metric will help you to determine the usability of your app and not just that, but also the value that users find in your app's features, new and old.

If you choose to ignore users' needs, your app will start to lose popularity.

4. Specific goals. Most developers have a certain vision of how each user will use their app, usually envisioning a specific task to complete.

When tracking specific goals, look at the steps or events that you want users to accomplish and look at the percentage of people that are completing those actions.

Engagement, retention and goals can be tracked by integrating analytics tool into your app, like Flurry, which is available for free, and Localytics, a tool that has a free and paid version.