Never mind the definition of terrorism (let alone the definition of poverty). As the Guardian wrote in 2001:

While most people agree that terrorism exists, few can agree on what it is. A recent book discussing attempts by the UN and other international bodies to define terrorism runs to three volumes and 1,866 pages without reaching any firm conclusion.

Let us for this particular exercise say that terrorism is the deliberate taking of civilian (i.e non-combatant) lives for ideological purposes.

Some scholars have come to the conclusion that there is no link between poverty and terrorism. Indeed, there is absolutely no denying that the world’s have-nots far outnumber the haves, and that most have-nots are anything but terrorists. Nor can it be denied that ISIS, to take an example, is headed by a man with a university doctorate. I quote Wikipedia (12/03/2017):

In an interview with The Daily Telegraph, contemporaries of al-Baghdadi describe him in his youth as being shy, unimpressive, a religious scholar, and a man who eschewed violence. For more than a decade, until 2004, he lived in a room attached to a small local mosque in Tobchi, a poor neighbourhood on the western fringes of Baghdad, inhabited by both Shia and Sunni Muslims.

With a doctorate, he would at least not have been destitute. Whether he lived in relative poverty because he had no choice, or out of solidarity with the poor, or for tactical reasons must be a matter of speculation, judging from the above cited Wikipedia article.

At any rate he did live in relative poverty and he was detained at Abu Ghraib for 10 months. I have never been to Abu Ghraib, but I have been given to understand that detention there was no tea party.

Have you, dear reader, ever felt that you or somebody you cared for had been subjected to gross injustice? Now if you, as I, enjoy a reasonably comfortable living standard, your anger will probably have abated somewhat after a few days. You would certainly not seriously contemplate terrorism. Those of us who have jobs to tend, and family and loved ones to inspire with hope and love of life, cannot allow our minds to be poisoned by bitterness and hate.

But if even the simplest chores of survival were a minute by minute uphill battle and if any of your loved ones had been killed or tortured, believe me: You would be a potential terrorist. You would perhaps not be willing to kill, but you might be willing to harbour a killers, feed him and refuse to give him away, etc. That would make you an accomplice in terrorism, which in many countries is as serious an offence as active terrorism.

I fear the methods that have been employed in the studies referred to above are seriously flawed.

Poverty alone may not be enough to drive a man or woman off the cliff, and successful terrorist groups (whether white-supremacist or religious) are contingent on having leaders who are moneyed and/or educated and who are probably, more often than not, psychopaths. But the foot soldiers who make up their armies are as much victims as their victims, cf. BBC outline of terrorist groups in Africa:

They are given the feeling that they are a very important person and that martyrdom is something to aspire to – the anger over their deprivation is lowered to a feeling of comfort, to a point where the only thing they aspire to is a collective action.

Whether that action leads to their survival or death doesn’t really matter any more.