Abstract
Keeping in mind the importance of telecommunications sector for India especially post the reform of 1991, the study seeks to study the causal relationship between telecommunication and economic growth for selected panel of 17 Indian states by implicitly taking into account panel heterogeneity. Using Hurlin–Venet causal mechanism, the study investigates homogeneous causality (HC) as against heterogeneous causality (HEC). Homogeneous non-causality and HC hypothesis both of which assume homogeneity are rejected in both the directions thereby implying that Indian panel is made up of heterogeneous cross sections. After this HEC tests are conducted namely heterogeneous non-causality (HENC) and HEC for each and every cross section. The results from HENC and HEC test show that six states show up unidirectional causality from economic growth to telecommunication, four states show unidirectional causality from telecommunications to economic growth, four states show up bidirectional relationship and three states show up no causality. The results are robust to different lags for both our dependent as well as independent variables. This implies that state level differences are very much relevant for India and thus policies suitable for each state would be guided majorly by direction of relationship that is true in a particular state economy.
Introduction
From the age of letters, telegrams and typewriters, the world today has entered into the age of smartphones, computers, internet and hi-tech technology that has revolutionised the 21st century. The smartphones have established themselves as the ‘Swiss army knife’ of the tele world which acts as a hub for myriad activities. The changes in the technology have been so rampant that what seems to be new today loses its novelty in just a few months. This is spurting innovations in the field of ICT. The pace of transformation has been staggering. From 1G technology that dates back to 1970s, 2G technologies found its origin in 1990s. Thus the pace of transition was almost 20 years. But the subsequent upcoming generations have witnessed a quick period of progression. The world moved from 2G to 3G in just 14 years while the shift from 3G to 4G took place in just 12 years. The likely period for 5G to unfold is 2020. So what emerges out from this technology evolution is that subsequent transformation is taking lesser time to unveil. This marks off innovations that are characterising the Information and Communication Technology (ICT) industry world over. World Bank (2016) has identified three mechanisms that act as mediator between digital technology and economic growth. These are: inclusion, efficiency and innovation (Fig. 1).

A Framework for Internet and Economic Growth.
Telecommunications and Growth Causality (International as well as Indian Evidence). 1
While all the below presented studies exclusively talk about casual patterns at the overall level, none focus on subnational causal behaviour. In this vein we have selected works by Shiu and Lam (2008) that provide evidence for heterogeneous causality (HEC) behaviour for Chinese economy as well as for set of 105 countries of the world. For China, they found out that overall causality ran from gross domestic product (GDP) to teledensity while for high-income region the pattern was same but for other regions (Central and Western regions which are low income regions) there was no causality at all or it ran from GDP to teledensity. Similarly for 105 countries which were segregated on the basis of income, for high income countries the causality was bi-directional while for low- income countries it was from growth to teledensity.
The above review of literature highlights numerous gaps: First, despite extensive research on causality between telecom and economic growth, the research has still been inconclusive. Especially taking the Indian case, very few papers come to our knowledge that talk about causality. Despite dealing with the time series analysis the results are not unanimous. Second, the base of Indian studies is time series with a complete absence of any paper that has taken into account subnational causality aspect. In addition to that, dealing with panel studies offers added advantage in the form of verifying homogeneous causality (HC) against Heterogeneous Causality (HEC) which is the major novelty of the paper. The case for HEC is more relevant for panel studies because of higher degree of heterogeneity that is suspected among the cross sections. This HEC hypothesis is very much validated in other domains particularly for energy–economic growth relationship that too for the two most important economies of the world, the USA (Mahalingam and Orman 2018) and (Akkemik et al. 2012; Zhang and Xu 2012) China, and also for India. Having verified HEC between other economic variables particularly with respect to causality, the need for study is immense because the primary objective of the research is to study subnational causal relations. The case for differences in subnational causal relation is already validated by Shiu and Lam (2008) and the same can be expected in Indian case.
The research is undertaken with the sole objective of studying the causal behaviour between telecommunications and economic growth for 17 Indian states for the period 1991–2017 by addressing the issue of heterogeneity. Given the background of major surge in telecommunication facilities in India especially post reform of 1991, the results from the paper can have far reaching implications. As far as the contribution that the study makes to the overall subject, these can be found along three major lines: To the researcher’s knowledge, this study is the 1st one to discuss about causal process between telecommunications and economic growth for the panel of 17 Indian states so as to study the profound regional differences that are likely to exist within India. Secondly, this study makes a sharp departure from the existing causality studies by distinguishing between homogeneous and heterogeneous causality. Thirdly, the research is driven by the set of more recent econometric tools and methodologies comprising of Cross-sectionally Augmented Im–Pesaran–Shin (CIPS) unit root test and Westerlund cointegration test (both of which are 2nd generation testing tools which are more valid in the presence of cross section dependence (Latif et al. 2018) and Hurlin–Venet causal mechanism. Such an application of advanced econometric techniques imparts robustness and rigour to the analysis carried out.
Despite being a regional study catering only to the Indian states, the study offers its conclusions to the wider audience. Also it attempts to engage itself with the methodological debate centring on panel studies which are subjected to frequent changes. The application of Hurlin–Venet process and the subsequent validation of HEC in Indian case provide a strong case for verifying such patterns across other economies of the world. This can initiate a whole new set of literature discussing along the lines of heterogeneous causal relation instead of homogeneous relation which has been the major assumption of Granger causality process.
This study is divided into five sections including the present introductory one. The 2nd section provides the information on the database. The 3rd section details the methodology used in this study. The 4th section offers the empirical results and discussion of the analysis. Conclusions and relevant policy implications are given in the last section, that is, 5th section.
To perform the causal analysis between the variables, we require two variables of telecommunications and economic growth. For telecommunications, we have used teledensity (number of telephones per 100 people) while for the variable of economic growth we have relied on three estimates: per capita net state domestic product (Y); gross domestic product (G) and net state domestic product (N). The data are collected for a set of 17 Indian states from 1991 to 2017. These states are Andhra Pradesh, Assam, Bihar, Gujarat, Assam, Haryana, Himachal Pradesh, Jammu and Kashmir, Karnataka, Kerala, Madhya Pradesh, Maharashtra, Odisha, Punjab, Rajasthan, Tamil Nadu, Uttar Pradesh and West Bengal. Few Indian states witnessed bifurcation over this time which includes Uttar Pradesh, Bihar and Madhya Pradesh in 2000 and Andhra Pradesh in 2014. In order to maintain coherence in the dataset, the states originally (before bifurcation) have been retained in the analysis.
Methodology
The estimation strategy adopted in this study is given in the Figure 2. To test the cross section dependence we employed Lagrange Multiplier (LM) test (Breusch and Pagan 1980; Pesaran 2007). The notation of LM test is given as:
Where
While the Pesaran test of cross section dependence is given as:

Panel Estimation Procedure.
After checking the degree of dependence (or independence) as the case is, we conduct preliminary testing of stationarity and cointegration properties of our database. For this, we employed both CIPS (Im et al. 2003) and Cross-sectional Augmented Dickey–Fuller test statistic developed by Pesaran (2007), which can be expressed as follows:
Post this, we carry out the cointegration using Westerlund’s (2007) testing procedure. Under this, we have four different statistics: Panel statistics (Pt and Pa) and group statistics (Ga and Gt). The tests are implemented by inferring whether the error-correction terms are zero as a test for the null of no cointegration. The error-correction-based panel cointegration tests allow for cross-sectional dependence and heterogeneity both in the long-run cointegrating relationship and in the short-run dynamics.
The process of assessing the causality is not simple especially in panel data and choosing the most appropriate technique is the major corner stone for research. This is because it addresses the empirical and theoretical issues in a more explicit way. The conventional Granger causality technique is ridden with most important econometric issue of homogeneity across cross sections which in the present times is hard to meet. To address this issue, Erdil and Yetkiner (2005) grouped the panel causality into two broad categories: one in which the auto regressive coefficients and slope coefficients are taken as variables in the panel Vector Autoregressive (VAR) model and on the other side Hurlin and Venet (2001) suggested a method wherein these coefficients are assumed to be constant. The main criterion to decide between the two is the time length of the study. If the time span is long, then the 1st method is adopted otherwise we go with the 2nd approach. Given the time frame of this study, 1991–2017 (27 years), we go with Hurlin–Venet approach. In this technique, we make use of fixed effects that are time invariant and the lags of dependent variable are included in the regression model. Thus, this study employs heterogeneous fixed effects dynamic panel data estimation procedure. The regression equations for estimation are given below:
Here i refers to the individual cross sections (which in our case is Indian states), t denotes the time and l is the number of lags, α, β and γ are the parameters that are to be estimated. Here the slope coefficients β′s are assumed to be constant over a period of time but vary across cross sections. Equation 1 tests for causality from economic growth to telecommunications while the Equation 2 tests for the other causality direction.
Hurlin–Venet Causality Hypotheses.
Cross Section Dependence Test Statistics.
Cross Section Dependence Test Statistics.
*** means significance level of 1 percent.
Unit Root Results.
* means 10% significance level.** imply significance level of 5%.*** implies significance level of 1%.
The results from unit root tests clearly state that all our variables are stationary at first difference. Thus the order of integration of the variables is I(1). This non-stationary property of the data is revealed when the estimations are conducted using different models involving intercept and trend, following which long run equilibrium relationship between the two variables is investigated using cointegration analysis.
Westerlund Cointegration Test.
Test Results for Homogeneous Non-causality (HNC Hypothesis).
***, ** and * imply significance level of 1%, 5% and 10%, respectively.
For the causality running from economic growth to telecommunications, we see sufficient evidence against no causality hypothesis. This is true for all definitions of economic growth as well as for all three lags. Most of the test statistics are significant at 1% level. Same is true for causality running from telecommunications to economic growth where also we see that all the test statistics are highly significant (level of significance being 1%). Thus in all we can say that there does exist causality between both the variables in both the directions.
Having established the presence of causality, the next step is to check whether that causal behaviour is homogeneous or heterogeneous. First of all we try checking the HC relationship. The results from HC process are tabulated in the Table 7.
Test Results for Homogeneous Causality (HC Hypothesis).
***, ** and * imply significance level of 1%, 5% and 10%, respectively.
Because the hypothesis of HC is rejected vehemently in both the directions, we now seek to work out the heterogeneous causal relationships. The heterogeneous causal relationship is tested in two steps: 1st, the causal relationship is studied for each and every cross section of the panel and 2nd, the cross sections that depict causality in the 1st step are then jointly taken up as a group to test heterogeneous non-causal relationship.
In the 1st step we run our regression model for all 17 cross sections in both the ways subject to the restriction i of βl = 0. Thus for the causality running from economic growth to telecommunication, we will run the regression equation 51 times (17 × 3) and similarly for the causality running from telecommunications to economic growth again we will run the model for 51 times. In all, 102 regressions equations will be calculated. The results from HEC running from growth to telecommunications are presented in the Tables 8 and 9
Results from Heterogeneous Causality Between Growth and Telecommunication.
Results from Heterogeneous Causality Between Telecommunications and Growth.
After carrying out the 1st step of HEC, we now move onto carrying the 2nd step. For this we take up 10 Indian states as a single group to test HENC and the results are presented in the lower panel of Table 10. As is clear, in all the six cases, that is, for all definition of economic growth and at all lag values, the F-statistic is greater than the critical limit of F thereby rejecting the null hypothesis for all these subgroups of Indian state.
Tests of Heterogeneous Non-causality.
Based on the evidence of causality direction in the 17 Indian states, these can be grouped under four heads:
Unidirectional causality from telecommunication to economic growth: These include states of Bihar, Gujarat, Rajasthan and Tamil Nadu. Here we see that the states are in fact scattered rather than being located in a particular geographic location. While Gujarat and Rajasthan are located on the West, Tamil Nadu in the South and Bihar in the North. Unidirectional causality from economic growth to telecommunication: This group includes Andhra Pradesh, Assam, Haryana, Maharashtra, Odisha and Punjab. Here again a scatter plot is validated wherein some are coastal states (Maharashtra, Odisha and Andhra Pradesh) and others are landlocked states (Punjab and Assam). Bidirectional causality between telecommunication and economic growth: Only four states of Indian origin show up causality in both the directions. These include Himachal Pradesh, Madhya Pradesh, West Bengal and Kerala. No causality between telecommunication and economic growth: The three states of Jammu and Kashmir, Uttar Pradesh and Karnataka show causality in none of the direction.
The above set of states can be well elucidated in the form of a geographical map (Figure 3).

Heterogeneous Causality Map of Indian States. 2
This study brings to the forefront the case of HEC between telecommunications and economic growth for 17 Indian states. After applying Hurlin–Venet process of Granger causality, we strongly refute the assumption of HC which has been upheld by the researchers in this domain. The results from the causal process are summarised as: HC is rejected in both the directions leading us to test for HEC; HEC holds for 10 states from economic growth to telecommunication (Supply led hypothesis) and eight states show causality from telecommunications to economic growth (Demand led hypothesis) and three states show up no causality (Neutrality hypothesis). The results are robust to different lags as well as definition of our economic growth variable. Thus, heterogeneous causal pattern between economic growth and telecommunications can mainly be attributed to differences among states on account of development, population, natural resources, consumption patterns and many others.
Thus, we can say that instead of universal causality direction, we find out that multiple hypotheses are being validated at subnational level. Given these differences across Indian states a word of advice that is most suitable here is that regional differences need to be accounted for, at the time of policy recommendations because it is more of a state affair now. What is true at the national level might not be true for all its constituent units and that is exactly what is replicated in this study. The states wherein the two variables are intertwined are at an advantageous position because each of them serves as a causal factor for the other. For them, both growth and Information and Communication Technology (ICT) are equally important and thus emphasis on either of them will prove to be fructuous because of feedback effect that exists in such state economies. Shock to either of them will ravage the growing process. The states which do not show any causality from telecommunications to economic growth could be attributed to lower penetration rates than the ‘critical mass’ level which is needed for telecommunication to show up their impact on growth (Shiu and Lam 2008).
Given the above heterogeneity in causal relation which is one of its kind to work along these lines, the study is not bereft of limitations. The most important of this is the case of bivariate analysis. Because this study takes into account a bivariate relationship, this offers the problem of omitted variable bias. So the future line of research needs to take into account additional variables like capital formation, labour force among others to study the direction of causality.
Footnotes
Data Availability Statement
The data needed for the present empirical research is a part of doctoral thesis hence cannot be made available although, the same can be made available on request.
Declaration of Conflicting Interests
Funding
The authors received no financial support for the research, authorship and/or publication of this article.
