What is the scientific effectiveness of “street preaching” as a method of evangelization?
Scientifically methodology seems to almost be non-exist in this subject matter. However history show that it is effective in making conversations. The lives of several historical persons bears this out.
We can see how St. Paul changed his preaching approach after his preaching in Athens about the Unknown God.
Historically speaking street peaching has been proven to be an excellent method of evangelization. Some believe that it dates back to biblical times. Had not Jonah in the streets of Nineveh had not preached to the inhabitants of Nineveh, would they have repented of their sins!
Open-air preaching, street preaching, or public preaching is the act of evangelizing a religious faith in public places. It is an ancient method of proselytizing a religious or social message and has been used by many cultures and religious traditions, but today it is usually associated with Evangelical Protestant Christianity.
Early Methodist preachers John Wesley and George Whitefield preached in the open air, which allowed them to attract crowds larger than most buildings could accommodate.
Motives for open-air preaching include to glorify God and to fulfill the command to preach and make God's Word known.
Some who believe street preaching is Biblical include examples such as Jesus in the Sermon on the Mount that of the prophet Jonah, who reluctantly obeys the command of God to go to the city of Nineveh and preach "Yet forty days, and Nineveh shall be overthrown!". Others listed include Paul's speech to the Athenians in Acts 17. However, others believe from scripture that Jesus was not technically a street preacher nor could possibly be one, "He shall not strive, nor cry; neither shall any man hear his voice in the streets."
The Christian Apologetics and Research Ministry lists the "many examples of street preaching in the Bible" as including Noah, Solomon, Ezra, Jeremiah, Jonah, John the Baptist, Jesus Christ, Peter, Paul, Phillip and Apollos.
St. Dominic and the first generations of Dominicans were seen all over Europe preaching the streets of various European cities.
St. Dominic's Plan Unique
In its plan and purpose the Institute is unique, for of all the orders of the Middle Ages the Friars Preachers was the only one formally approved by the Holy See for the single purpose of universal preaching. It had occurred to no other founder of a religious institute to petition the Holy See for permission to establish an order in which the practice of apostolic preaching, after long years of scientific training, should not be a temporary privilege but an inherent right.
It is true that, a century before, St. Norbert had received for himself a general permission to preach wherever he would. Afterwards it was suggested to him by the Bishop of Laon that he found an order for the purpose of continuing his work after his death. This he did, but provided for the administration of parishes as well as preaching in his institute. And although the followers of St. Norbert rapidly increased in number until they became a most numerous body, the division of their efforts between parish work and the larger apostolate of preaching rendered it impossible for them adequately to supply the urgent needs of the pulpit. This is clearly shown by the burning words of the Fathers of the Fourth Lateran Council deploring the lack of effective preaching in the Church. Nor does St. Norbert seem to have adopted any special measure to qualify them as a body to preach more effectiiely than the parish clergy. To St. Dominic, therefore, must be accorded the credit of having first conceived the splendid idea of an institute wholly given over to the extirpation of heresy and the propagation of the Gospel to the ends of the earth. The administration of parishes did not enter into its interests because St. Dominic desired his disciples to possess not a local but a universal character -- to preach the Word of God not one day in the week but every day. The chapter of 1228 decided the matter formally when it forbade the brethren to accept churches that carried with them parish obligations.
St. Francis of Assisi often preach in villages and in the outdoors!
I've heard the quote once too often. It's time to set the record straight—about the quote, and about the gospel.
Francis of Assisi is said to have said, "Preach the gospel at all times; when necessary, use words."
In his day, Francis was known as much for his preaching as for his lifestyle.
He began preaching early in his ministry, first in the Assisi church of Saint George, in which he had gone to school as a child, and later in the cathedral of Saint Rufinus. He usually preached on Sundays, spending Saturday evenings devoted to prayer and meditation reflecting on what he would say to the people the next day.
He soon took up itinerant ministry, sometimes preaching in up to five villages a day, often outdoors. In the country, Francis often spoke from a bale of straw or a granary doorway. In town, he would climb on a box or up steps in a public building. He preached to serfs and their families as well as to the landholders, to merchants, women, clerks, and priests—any who gathered ... - Speak the Gospel