Currencies are one of the most difficult asset classes when it comes to performing fundamental analysis. Several different factors affect their worth, ranging from domestic interest rates, inflation, trade balance, macroeconomic & geopolitical stability, and even global currency flows are just a few factors that impact the worth of a currency.
Narrowing down and isolating each factor attributable to appreciation and depreciation of respective currencies is difficult and requires immense statistical knowledge coupled with a rigorous understanding of macroeconomics.
In this post we'll try to analyse a few currencies with the help of the platform Koyfin (Koyfin.com*), and their price fluctuations via looking at potential correlations between dominating exports of a country and the value of that country's currency.
By keeping it simple and looking at different exported commodities, our aim is to provide an intuitive understanding of a nation's exports and the value of a currency.
First we will look at Russia as an example, which has a fairly large share of their revenues and GDP-growth derived from the price of crude oil, as they're one of the largest crude producers and exporters in the world.
Since the price of crude oil is priced in $-dollars globally, this leads to a sale in dollars, which needs to be exchanged back to Rubles, creating a higher demand for Rubles driving the value of the Ruble higher.
The price of crude-oil itself, affects the exchange-rate of the Russian Ruble because it leads to different quantities of Rubles being purchased.
A higher crude-price, leads to more Rubles being available for purchase, than a lower crude-price, which leads to less Rubles being available for purchase.
Graphically we can see that there is a correlation between the value of the Russian Ruble and the price of Brent-crude oil.
The correlation-relationship is not always as strong as we'd like, but it is sufficient in demonstrating and proving the intuitive basis that the value of a nation's currency is intimately tied to its main export products.
Since crude-oil is not the only the major commodity being exported out of Russia, with agricultural products and metals making a up large of its exports. We're going to plot the weighted Thomson Reuters Commodity Index (CRB-index*).
The index comprises 19 commodities: Aluminum, Cocoa, Coffee, Copper, Corn, Cotton, Crude Oil, Gold, Heating Oil, Lean Hogs, Live Cattle, Natural Gas, Nickel, Orange Juice, Silver, Soybeans, Sugar, Unleaded Gas and Wheat. 
We clearly see that there is a correlation between the value of crude oil and the CRB-basket of commodities, tied to the value of the Russian Ruble.
Arguably, we haven't factored in geopolitics, interest rates and other important factors that drive the value of the currency, but our aim is to isolate and stick to few factors as it reduces the complexity that is otherwise associated with currency-valuation.
In our example with Russia it is useful to be accustomed to the fundamentals of the underlying commodity/commodities that affect the value of the Russian Ruble.
Fundamentals of crude-oil are heavily affected by supply & demand, with OPEC being one of the key market drivers in establishing levels of different quotas of production, and in extension affecting crude oil prices.
A bullish outlook on the fundamentals of crude, equates to a higher Russian Ruble, a bearish outlook on the fundamentals of crude, equates to a lower Russian Ruble.
This analysis extends itself to other commodities that are used in correlation analysis. Brazil's main export e.g. is soybeans, so the value of the Brazilian Real is influenced by the price of soybeans.
OEC: The Observatory of Economic Complexity
https://atlas.media.mit.edu/en/
Is a fantastic tool when it comes to analysing and providing a visual and intuitive sense of the main exports of a country that can be used in finding suitable commodities that are used in correlation analysis for currency valuation.
Below we see the main exports of Russia;
https://atlas.media.mit.edu/en/profile/country/rus/
And Brazil..
Thus using the OEC, we get a quick glimpse of the main exports of a country, and can utilise that information in order to find suitable commodities in our correlation analysis.
It is worth noting that the example of Russia is an outlier as its economy is heavily depended on energy-sector, and that exports make up a substantial amount of calculated GDP.
Countries whose economies are heavily export-reliant will show stronger correlations between the value of their currency and their exported products.
This means that countries such as the U.S, which as of now, is the world's biggest producer of crude oil, won't display statistically significant relationships between the price of crude oil and the U.S. dollar as its economy and GDP is built on different sectors that include domestic consumption and is less export-reliant.