The 2016 and 2020 Puerto Rican Gubernatorial elections both saw decently close contests, with the margin in 2020 being almost half of 2016. As such, the swings under the surface to get to that result are telling about the diferent candidacies of Pierluisi and Carlos Delgado.
Broadly, Pierluisi improved on the PNP's 2016 showing in the more liberal and some moderate Areas of the Island, such as the San Juan, Caguas, Guayama, and Mayagüez Metros. (In addition to Patillas which swung to the PPD due to a home Municipio effect with PPD candidate David Bernier)
In contrast Delgado Altieri improved on the PPD's 2016 showing in the more conservative and moderate areas, such as his home area of the Northwest in and arround Isabela, the Arecibo Metro, Aguadilla Metro, Fajardo area, Rio Grande area Lares, Maricao and Adjuntas.
In addition to the PNP-PPD Swing, there was also the fact that both major parties lost significant Vote share between the 2016 and 2020 Elections, going from 80.7% to 61.3% of the combined vote. Taking a look below, we see where the major parties lost the most votes.
Those places being, the Liberal Areas of the Greater San Juan, Caguas and Guayama metros, the Ponce and Mayagüez areas, and the Municipio of Guánica.
In addition to the moderate Humacao Metro, and Conservative Municipios of Vega Baja, Manatí, Florida, Adjuntas, Canóvanas, Juncos and the Fajardo-Rio Grande area.
Taking a look at the Senate Districts we find that in Terms of PNP-PPD Swing, Pierluisi inproved on the PNP's 2016 showing the most in the San Juan Senate district, and we also find that Charlie inproved on the PPD's 2016 showing the most in the Arecibo Senate district, as a consequence of the municipio swings examined above.
In terms of the PNPPD-Other Swings, the areas that swung most towards the non main parties were the San Juan Metro Districts of San Juan and Bayamón, as well as the Adjacent districts of Carolina and Humacau which contain the Urban areas of Carolina and Caguas, as well as some liberal suburbs.
Secondly, the District that swung the least towards other parties was the Mayagüez-Aguadilla Senate District, mainly due too Charlie's strength in the Isabela-Aguadilla area.
Looking to the house districts, we find that Pierluisi inproved upon the 2016 PNP performance in 23 Districts, and Charlie inproved upon 2016 PPD performance in 17 districts, Pierluisi Inproving the most in the 4th District, in San Juan and Charlie inproving the most in the 14th district in Arecibo/Hatillo
Lastly, taking a look at where the other parties inproved uppon 2016, we find that combined they inproved in all the districts, Inproving the most in House District 3 (by 40.06%), and the least in House district 17 (by 19.61%).
All in all, (while not a 1-1 correlation as there are some exceptions, such as Vega Baja and Manatí), the areas that swung to Pierluisi and the other Parties by the most, tended to be in Liberal/Moderate areas, while the areas that swung to Charlie Delgado and the least to other parties tended to be in Moderate/Conservative areas.