How Music Works: Patterns in 1300 Popular Songs

Music carries that sense of infinity in its creation, making it a transcendental art beyond the human virtues and miseries of its performers and creators. Associated with the most rational mathematics and the most intangible muses, popular music—the kind we hear on the radio—has its down-to-earth and cultural anchor in how it is composed. That's why a musician conducted a study on patterns in popular music: which scales and chords are typically used to compose the most famous songs. Is composing with these keys a reason for success? A consequence of education? Convenience? Some biological mandate? The first part of the answers is here, in this analysis of patterns in popular songs.

Patterns in Popular Songs

In this original article from Hook Theory, we'll look at statistics gathered from 1300 choruses, verses, etc. of popular songs to uncover answers to some basic questions. First, we'll examine the relative popularity of different chords based on how often they appear in chord progressions of popular music. Then we'll start to see the relationships between different chords. For example, if a chord is found in a song, what can we say about the probability of guessing which chord will follow it? At NeoTeo we bring you a Spanish and commented version of this article that got hundreds of musicians talking in the blogosphere.

The Database

To make quantitative statements about music, you need data—lots of it. There are plenty of places to get it, as some guitar and piano sites have tons of information about the chord progressions used in songs, though the quality of that information is not very high. Equally important, the information is not in a format suitable for statistical collection. So, over the last 2 years, the author of this study has been slowly and painstakingly building a database of songs taken mainly from the Top 100 charts, analyzing them one by one.

Currently, the database has more than 1,300 indexed entries. The genre and where they come from matters. This is an analysis of popular music, excluding more complex genres like jazz or classical, so the results are not meant to be universal. Each studied song entry contains raw information about chords and melody, as well as information about note arrangement and instrumentation.

The author, after warning us about the database and its composition, tells us that many questions can be asked and answered through the analysis of these songs, so the introduction to a series of articles begins with the first one:

Are Some Scales and Chords More Used Than Others?

The researcher's answer is a resounding yes, and if you don't believe it, look at the results: Songs are written in different scales, so a song written in C# (C sharp major) will have lots of C# chords, while a song written in G will probably have lots of G. When we analyze, the fact that G chords are more popular than C# chords is likely a reflection that they are easier to play on guitar and piano. So let's change the question to something more informative and less predictable, for example: What are the most popular scales in the songs of this database?

The answer is C major and A minor. After that, there is a general tendency toward scales with fewer sharps and flats, but this is not universal and, as always throughout this text, the results are based on the database.

What Are the Most Common Chords?

Without a doubt, when reviewing this type of analysis, it is much more interesting to see songs written in a specific, common, and generally easy-to-identify scale. This way, direct comparisons between one and another are possible and more illuminating. To do this, the researcher transposed all the songs in the database to the key of C major. This makes visualizing chord progressions more intuitive and, without a doubt, revealing. With this done, the relative frequency of the different chords has been plotted in descending order.

For the researcher, the results were as expected: first, C major is a very common chord in songs written in C (that's the I chord in Roman numeral notation or Nashville Number System). However, F major and G major, the IV and V, are used equally often. What wasn't as predictable is that F and G appear in more chord progressions than C.

C is the tonal center here, and one might expect it to be ubiquitous. Interestingly, the omission of this chord in some sections of songs is more present than expected. As an example, the researcher gives us the song that reminds us of DiCaprio and Winslet's Titanic sinking in the Atlantic, My Heart Will Go On by Celine Dion. In the example analyzed in the previous image, we can see that despite its tonal correspondence, the chorus and verse only contain one C chord.

4 Chords: The Key to Pop Songs

To continue with the scale of chord popularity, we have to talk about A minor (Am), but delving deeper into it won't entertain us or give as many answers as talking about the decline in use of the remaining chords. That is, Dm, Em, E, D, B-flat, and A, correlatively ordered among the most used. And what's important about this? Well, basically the largest percentage of songs we hear on the radio and that have been overwhelmingly successful are composed using 4 main chords: G, F, C, and Am to a lesser degree but notably distinct from the next on the list, Dm. That is, our musical culture (more popular, more commercial, etc.) has a recognizable pattern of 4 chords: G, F, C, and A minor. Interesting, right? But let's see why this might be the case according to the author of the original article.

The questions he asks are: “Is there a reasonable explanation for the relative popularity of these chords? Why are chords of minor importance so popular, while major chords are practically nonexistent?” He says the results can be easily explained with a bit of basic music theory, but he invites us to read the upcoming articles he will release on the matter. Boldly, I started thinking musically, and my theory on this is that these types of chords are the easiest to combine when using instruments from different families, but mainly piano and guitar, whose pedagogy makes those chords the most characteristic in learning and practice. Furthermore, transposing to minor keys is generally more accessible and harmonically more effective if you use major scales to write them. For example, from C major to A minor. That's basic theory indeed. Anyway, since I don't consider myself a musician or an expert in music theory, I'd rather you take this only as an a priori deduction. The transcendence of this 4-chord pattern and the rest of the most popular ones is such that many music composition programs give them a privileged place when building their interface. The example the author gives is GarageBand, and for demonstration, just one button (or a screenshot) is enough.

What Popular Relationships Exist Between Chords?

To better understand the question, what we're trying to figure out is which chord will generally follow one of the most used chords in a song written in a given key. For example, in a song written in C, which chords are most used to follow an E minor (Em) chord? The relationships, according to the author, can be in the dozens based simply on what is seen in the most popular songs, perhaps explained by sounding better to the general ear.

In this regard, the results from the author's research were quite decisive, even though he only took one example out of many he could have selected. Based on the graph, we can say that taking songs written in C, with an E minor in them, the chord that follows will be an F 59% of the time, or an A minor 34%, with the next most used being D minor at 4%. This illustrates the popularity of these patterns, which are more general than one might think when faced with the sense of infinite creativity that music seems to have.

So far, this is the first part of this homegrown study on the most popular patterns in popular music, but we have something to say about it. So below we close with a small conclusion on the matter.

Are These Results Definitive?

No. Like any study, whether done under scientific circumstances or not, the selection of test subjects, the method, and the way the results are chosen are subject to the author's subjectivity, but that doesn't take away from the relevance of the matter. For example, the rule of the 4 chords is well known in music, and it's basically explained by classical harmony rules that are implicit in popular music, even involuntarily through the instruments most commonly used for composing (piano and guitar). For example, on guitar, one of the most prevalent scales is E, as it is the one many guitar methods use to teach, and it's the most used in heavy rock. On piano, C is the most used for learning as well, and it's the scale to which compositions for other instruments are often transposed. In another family of instruments, we can see a preponderance of F or B-flat in brass instruments, for example.

In my opinion, in the final result of these popular songs, what impacts the most is the scale in which the singer's vocal range can move, since taking into account that transposing a song to another scale is simpler than asking Britney Spears to sing differently. Likewise, the current study takes into account the number of times chords appear, but not their duration during the song. In any case, the article seems really interesting in what it proposes, because beyond being able to explain the causes one way or another, the repetitive patterns in the most popular music are something that everyone, more or less, knows by ear.

Source: Hook Theory