The BJP and its allies won 38% of the vote in 2014 (File photo)
It is incorrect to refer to 2014 as a "Modi Wave".
Two concepts often get confused in election analysis: Wave vs Landslide.
A "wave" refers to a high popular vote of a leader or a party; popularity is assessed by the % vote the leader wins.
A "landslide" refers to the high number of seats a party wins. A simple definition of a landslide is when the winning party gets more than twice the number of seats that the second-largest party wins.
In our first-past-the-post system, if the opposition is divided, a low popularity rating i.e. a low percentage of votes can convert into a large number of seats.
In other words, a low vote % can turn into a landslide in seats if the opposition is fragmented.
An example of a "Wave" in popularity is the Janata Party in UP in the 1977 elections when it won 48% of the vote.
While Narendra Modi/BJP+ won a landslide in seats in 2014, there was no popularity "wave". Here's why:
1) In 2014, Modi/BJP won only 31% of the all-India vote. That is not a wave by any stretch of any definition, though it did lead to a Modi/BJP landslide in seats (272 seats was way above any other party).
Conclusion: this was a landslide in seats, not a wave in popularity in terms of popular vote.
2) The BJP and its allies won 38% of the vote in 2014. And 38% cannot be termed a wave in popularity. But once again, because of a fragmented opposition, the BJP+ allies won 336 seats.
Conclusion: this was a landslide in seats, not a wave in popularity in terms of popular vote.
3) In Uttar Pradesh in 2014, the BJP won 42.63% of the vote. Once again, that level of popularity cannot be termed anywhere near a "wave". Of course, the badly divided opposition converted this 42.6% into 71 seats (that is 90% of the seats in UP) which was correctly defined as a huge landslide in seats.
Conclusion: this was a landslide in seats, not a wave in popularity in terms of popular vote.
4) In the UP assembly elections in 2017, the BJP won 41.4% of the vote. This is not defined as a wave in popularity. However, the BJP won 325 seats out of 400 (i.e. 80% of the seats) which is clearly a landslide.
Conclusion: this was a landslide in seats, not a wave in popularity in terms of popular vote.