Here's how we ranked the best Caribbean islands

We recently published a list of the 25 best Caribbean islands - no easy task, considering the beauty and appeal of each island.

For this ranking, we used four criteria: accessibility, average cost of a hotel room, number of attractions, and a beach density index score, which we'll explain below.

We weighted these criteria equally, because getting there with ease can be just as important as perfecting your tan.

In most instances, we defined a Caribbean island as a single country, republic, or territory in the Caribbean. The US Virgin Islands are made up of three major islands - St. Croix, St. John, and St. Thomas - but we counted it as one since the archipelago is considered one insular area of the United States.

To determine accessibility, we searched Google Maps to see how long the journey is from New York City to the major airport on the island. Islands that offer direct flights from New York City had shorter travel times, and performed better on the list.

For islands with no direct flights from New York City, we added the flight time from New York City to a nearby major airport, an hour for a layover, and the flight time for an island-hopper flight to the final destination.

To determine the average hotel room cost, we sought out the help of our friends at Hotels.com. The hospitality site provided us with the average hotel room cost on each of the islands for the year of 2016.

To determine the number of attractions, we searched the island on TripAdvisor.com, a reviews-based travel website. We used the number of attractions, which includes beaches, landmarks, cultural sites, and outdoor venues.

To determine the beach density index, we divided the length of each island's coastline by its land area, as indicated in the CIA World Factbook. This metric rewards islands that have a relatively large amount of potential beachfront for their size.

In the slideshow, we assigned description words to the island's beach density index score:

• Low: 0.0 - 0.2
• Moderate: 0.21 - 0.5
• High: 0.51 - 0.8
• Very high: 0.81+

When it was time to crunch the numbers, we normalized the data in each criteria so that each sub-score has a mean of 0 and a standard deviation of 1.

This common statistics technique allows us to preserve some of the relative size information (e.g. if one island has twice as much coastline than another island, it will get a much better score than if it had just 10% more coastline), while putting each variable on a common scale so we can meaningfully average them.

Melia Robinson and Talia Avakian contributed to an earlier version of this post.