The rating mostly takes freedom of movement for passport holders into account to determine a country's ranking.
The Henley & Partners website maintains that, "Visa requirements are also an expression of the relationships between individual nations, and generally reflect the relations and status of a country within the international community of nations."
Latvia scored 160 on a scale of 218 in the rating, while Estonia and Lithuania scored 159.
That means that Latvian nationals can enter 160 countries without a visa.
The best passports in the world are thought to be those held by nationals of Germany and the United Kingdom.