Nagaland, an Indian state bordering Burma, saw dramatic growth in the number of Christians during the 20th century . Composed of 16 separate tribes with different languages, the Naga people use English as their predominant language, which has undoubtedly helped the spread of Christianity. The growth of Christianity among 13 of the tribes has been documented by Paul Hattaway , showing substantial church growth through the 1950s and 1960s, with a massive increase in growth from 1976. Reading the narrative  there had been a series of evangelistic campaigns with sporadic and regional revival for 20 years, but then from 1976 there was a nationwide outpouring of the Holy Spirit, a national revival. By 1980 the church had increased by 55% in 4 years; from 26% of the Christian population in 1976, to 41% of the population in 1980 .
The Naga churches were largely Baptist, having been founded by such missionaries earlier in the 20th century. The Baptist church membership data for the period was obtained by Edwin Orr :
Year 1975 1976 1977 1978 1979 1980 1982
Membership 132,495; 134,682; 162,000; 179,047; 188,779; 209,382; 220,617
At the time of the revival the Naga state was largely closed to outsiders due to tensions with the Indian government. Thus the revival was a purely internal affair and ideal to compare with the Limited Enthusiasm model . The starting date for the revival was1976 , where the church had experienced a moderate increase from the previous year. Thus the comparison between data and model runs from 1976 to 1982, with the 1979 data excluded, as it is lower than expected .
The model simulation, given in figure 1, shows a good fit to all points (except 1979), with a reproduction potential of around 1.46. The enthusiastic period for the Nagaland revival is 6 months, which is 8 times larger than that of the 1904/5 Welsh revival, which explains why the revival in Nagaland lasted so much longer than in Wales. This longer enthusiastic period may well be due to a lower population density in Nagaland, compared with Wales, with the associated longer journey and communication times.
|Figure 1: Church Membership Nagaland and Limited Enthusiasm Model
The huge impact of the revival on the growth of the church can be seen by the reduction in the number of unbelievers, figure 2. The graph also shows an unusual nature of this revival, that in 1976 the church started with a large number of enthusiasts, who reached their peak in 1977 (figure 2), even though most of revival, and the growth, was after that date. Thus the revival appeared to be different to the normal pattern, where revivals start with only a few enthusiasts and take time to build. In this sense the enthusiasm was skewed towards the beginning of the revival, with much of the converts due to that initial enthusiastic momentum.
|Figure 2: Unbelievers, Enthusiasts & Inactive Believers, Nagaland, from Limited Enthusiasm Model
The skewed nature of the revival is also seen in figure 3, which shows the reproduction potential above the threshold for only one year after the start of the revival (indicated by the arrow) . Once a sufficient number of unbelievers were converted the threshold rose above the reproduction potential and the revival growth slowed.
|Figure 3: Reproduction Potential of Enthusiasts Compared with Revival Threshold
An attempt was made to fit the Limited Enthusiasm model to the data from 1975 in order to include a slow build up of numbers, but no satisfactory fit could be found. That leaves the question as to the origin of the large number of enthusiasts in 1976, given there had been little church growth before that year. There are at least three possibilities:
1. Between 1975 and 1976 a small number of enthusiasts made many new enthusiasts from the inactive believers – the renewal process;
2. Between those dates the spiritual life of the enthusiasts was building, raising the reproduction potential until it tipped the church into revival and produced a large number of enthusiasts;
3. There was a sudden mass baptism with the Holy Spirit of many believers between 1975 and 1976 – a Nagaland Pentecost.
All three theories could be tested by extensions to the limited enthusiasm model. However the reality may go back further than 1975. Hattaway notes [1, p.84] that the revivals of the 1960s had left the churches with a lack of trained leadership for the host of new converts. Thus it is possible that growth was being stifled for organisational reasons, rather than a lack of the Holy Spirit. They could not disciple converts fast enough, or retain them in church.
However in 1972 the evangelist Billy Graham visited Nagaland and was responsible for many leaders dedicating themselves to Christian service and to being appropriately trained. Over 100,000 had gathered to hear him preach in the capital, Kohima. The following 4 years saw an increase in prayer meetings for revival with “tremendous demonstrations of God’s power” [1, p.85]. It is likely that by 1976 the new leaders were both spiritually and practically prepared to cope with revival and were a crucial part of the large number of enthusiasts at its beginning.
In that case it can be concluded that Billy Graham was a key catalyst in the huge Nagaland outpouring of 1976-1982, even though he was not there during the period! But his preparatory work was critical. Revivals come from the work of the Holy Spirit and good preparation.
References & Notes
 Hattaway P. (2006), From Head-Hunters to Church Planters, Piquant.
 The population here refers to the nominal Christian population, about 75% of the total population. The remainder of the total population were tribal religions, Muslims, Hindus etc. The 1970s revival was a phenomenon within the Christian community. The previous decades saw Christian growth at the expense of the indigenous tribal religions, but had left many with the name Christian but without the commitment and church attendance.
 Hayward J. (1999). Mathematical Modeling of Church Growth, Journal of Mathematical Sociology, 23(4), 255–292.
 There are at least three possibilities for the discrepancy in 1979.
Firstly, the reporting of church membership data can be delayed in a particular year if there were some mitigating circumstances. Given the ongoing conflict between the Indian government and the Naga state, and the difficulty of travel in the country, it easy to see how this can happen. If the 1979 figure had been genuinely low then the pattern would have carried on until 1980. However the 1980 figure follows from 1976-1978.
Secondly, there could be two phases to the revival; one ending in 1979, and another starting in 1980. This is not mentioned in Hattaway’s book , but that does not mean it did not happen.
Thirdly, the delays in the geographical spread of the revival could have hindered growth in one year. The Limited Enthusiasm church growth model, like the SIR epidemic model, assumes homogenous mixing. The Naga terrain, and varied ethnicity, is anything but homogeneous!
 The reproduction potential measures the strength of the revival. It is the number of enthusiasts, not just converts, that one enthusiast could potentially make during the whole of their enthusiastic period. The Limited Enthusiasm model shows that revival growth takes place if the reproduction potential exceeds a threshold. This threshold increases as the pool of potential converts, the unbelievers, gets smaller. Thus revivals end before everyone is converted.
Tags: Baptist, Billy Graham, Christian, Holy Spirit, Nagaland, Reproduction Potential, Threshold