Bidirectional Causality Research Articles

The association between IGF-1 levels and four types of osteoarthritis: a bidirectional and two-step mendelian randomization study.

Insulin-like Growth Factor-1 (IGF-1) plays a crucial role in the growth and metabolic functions of various tissues and cells in the body. Recently, there has been increased attention to the association between IGF-1 and osteoarthritis (OA). However, there is controversy in current research regarding the correlation between IGF-1 levels and OA. Furthermore, the specific manner in which Body Mass Index (BMI), a key risk factor for OA, mediates the impact of IGF-1 levels on OA remains unclear. This study aimed to investigate the bidirectional causal link between IGF-1 levels and OA in four body regions, and to explore how BMI influences the impact of IGF-1 on these types of OA. Two-sample Mendelian Randomization (MR) and its combined forms were utilized to investigate the bidirectional relationship between IGF-1 levels and four types of OA, as well as the mediating role of BMI in the impact of IGF-1 levels on OA. Data from various Genome-Wide Association Studies (GWAS) and multiple analytical methods, including inverse variance weighted, MR-Egger regression, and weighted median were utilized. Sensitivity analyses, such as MR-Egger intercept, Cochran Q test, leave-one-out, and MR-PRESSO, were conducted to ensure the robustness of the results. Higher IGF-1 levels are correlated with an increased risk for knee (OR, 1.07; 95% CI, 1.01-1.03; p = 1.49e-01; q = 9.86e-03), hip (OR, 1.13; 95% CI, 1.06-1.20; p = 7.61e-05; q = 7.44e-05), and hand OA (OR, 1.09; 95% CI, 1.01-1.17; p = 1.88e-02; q = 1.15e-02), but not spine OA but not spine OA (OR, 1.05; 95% CI, 0.99-1.10; p = 9.20e-02; q = 5.52e-02). Different types of OA do not affect IGF-1 levels. BMI mediates the increase in OA risk associated with higher IGF-1, including indirect spine OA risk through BMI. The study elucidates the bidirectional causality between IGF-1 levels and OA in various body parts, highlighting BMI's mediating role in the impact of IGF-1 levels on OA. This provides valuable insights for OA prevention, diagnosis, and treatment strategies. Future research will expand our study to include a broader spectrum of ethnicities and explore the underlying mechanisms involved.

Bidirectional causality between the levels of blood lipids and endometriosis: a two-sample mendelian randomization study

BackgroundObservational studies have found a correlation between the levels of blood lipids and the development and progression of endometriosis (EM). However, the causality and direction of this correlation is unclear. This study aimed to examine the bidirectional connection between lipid profiles and the risk of EM using publicly available genome-wide association study (GWAS) summary statistics.MethodsEligible exposure variables such as levels of triglycerides (TG), total cholesterol (TC), low-density lipoprotein (LDL), and high-density lipoprotein (HDL) were selected using a two-sample Mendelian randomization (MR) analysis method following a series of quality control procedures. Data on EM were obtained from the publicly available Finnish database of European patients. Inverse variance weighted (IVW), MR Egger, weighted median, and weighted mode methods were used to analyze the causal relationship between lipid exposure and EM, exclude confounders, perform sensitivity analyses, and assess the stability of the results. Reverse MR analyses were performed with EM as exposure and lipid results as study outcomes.ResultsIVW analysis results identified HDL as a protective factor for EM, while TG was shown to be a risk factor for EM. Subgroup analyses based on the site of the EM lesion identified HDL as a protective factor for EM of the uterus, while TG was identified a risk factor for the EM of the fallopian tube, ovary, and pelvic peritoneum. Reverse analysis did not reveal any effect of EM on the levels of lipids.ConclusionBlood lipids, such as HDL and TG, may play an important role in the development and progression of EM. However, EM does not lead to dyslipidemia.

Estimating the causal relationship between external debt and inflation in Jordan: evidence from an ARDL and Toda–Yamamoto approaches

Purpose This study aims to investigate the causal relationship between external debt and inflation in Jordan over the period 1970 to 2020. Design/methodology/approach The external debt–inflation nexus is examined within a multivariate framework by including other determinants of inflation, including money supply and the nominal effective exchange rate. This study uses an ARDL bounds testing approach to cointegration to test the existence of a long-run relationship between the inflation rate and its drivers. An error correction model is estimated to reveal the short-run dynamics of the series. The direction of causality among the variables is examined using a modified version of the Granger non-causality test due to Toda and Yamamoto (1995). The analyses control for the presence of structural breaks in the underlying time series. Findings The empirical results show that external debt and money supply have a statistically significant positive effect on inflation in the long run. The authors also find that a nominal depreciation of the Jordanian Dinar raises inflation rates in the long run. The Toda–Yamamoto Granger non-causality test findings reveal a statistically significant bi-directional positive causality between inflation and external debt, between the nominal effective exchange rate and inflation and between money supply and inflation. Practical implications Proper management of the exchange rate policy, money supply and external debt levels is crucial to control inflation rates in Jordan. Originality/value To date, the authors are unaware of any empirical study that examines the impact of external debt on inflation in Jordan, and the current study aims to fill this gap in the literature.

Exploring the Causal Relationship Between Migraine and Insomnia Through Bidirectional Two-Sample Mendelian Randomization: A Bidirectional Causal Relationship.

The intricate relationship between migraine and insomnia has been a subject of great interest due to its complex mechanisms. Despite extensive research, understanding the causal link between these conditions remains a challenge. This study employs a bidirectional Mendelian randomization approach to investigate the causal relationship between migraine and insomnia. Risk loci for both conditions were derived from large-scale Genome-Wide Association Studies (GWAS). The primary method of Mendelian Randomization utilized in this study is the Inverse Variance Weighted (IVW) method. Our findings indicate a bidirectional causal relationship between migraine and insomnia. In the discovery set, migraine had a significant effect on insomnia (OR=1.02, 95% CI=1.02 (1.01-1.03), PIVW=5.30E-04). However, this effect was not confirmed in the validation set (OR=1.03, 95% CI=1.03 (0.87-1.21), PIVW=0.77). Insomnia also had a significant effect on migraine (OR=1.02, 95% CI=1.02 (0.01-1.03), PIVW=2.67E-08), and this effect was validated in the validation set (OR=2.30, 95% CI=2.30 (1.60-3.30), PIVW=5.78E-06). This study provides meaningful insights into the bidirectional causality between migraine and insomnia, highlighting a complex interplay between these conditions. While our findings advance the understanding of the relationship between migraine and insomnia, they also open up new avenues for further research. The results underscore the need for considering both conditions in clinical and therapeutic strategies.

Causal associations between systemic lupus erythematosus and primary biliary cholangitis: A bidirectional Mendelian randomization study

ObjectivesThe association between systemic lupus erythematosus (SLE) and primary biliary cholangitis (PBC) has been increasingly recognized. However, the existence of causal connections between SLE and PBC has yet to be established. In this study, we aimed to investigate the bidirectional causation between SLE and PBC utilizing Mendelian randomization (MR) analysis. MethodsWe acquired summary data from Genome-wide association studies (GWAS) for SLE and PBC from the IEU Open GWAS and FinnGen database. The inverse variance weighted (IVW) was employed as the key method to ascertain the causality between SLE and PBC. Subsequently, a range of sensitivity analyses were applied. We also performed a fixed-effects model meta-analysis to combine the MR results from different databases. Moreover, multivariable MR were conducted to clarify the roles of potential confounding factors. ResultsOur univariable MR investigation provided compelling evidence supporting a causal relationship between SLE and PBC in both directions. Specifically, the IVW method demonstrated a strong casual effect of SLE on PBC (odds ratio (OR) = 1.17, 95 % confidence interval (CI) = 1.09–1.25, p < 0.001). In addition, the results of reverse MR analysis revealed that genetically predicted PBC was associated with an increased risk of SLE (OR = 1.39, 95 % CI = 1.32–1.45, p < 0.001). The sensitivity analyses indicated the absence of horizontal pleiotropy and heterogeneity. Furthermore, the causality between SLE and PBC remained significant even after adjusting for common risk factors in the multivariable MR analysis. ConclusionsOur study provides statistical evidence of a potential causal relationship between SLE and PBC, but further research is needed to the explore of the underlying mechanisms of these disorders.

Characterization of Drought Propagation in the Han River Basin Based on Chaos Theory and Nonlinear Dynamic System

This study characterized drought propagation in the Han River basin based on chaos theory and nonlinear dynamic systems. The nonlinear complexity of drought propagation, specifically between meteorological and hydrological droughts, was identified using convergent cross-mapping and phase-space reconstruction techniques. The analysis results on the causality of drought propagation between meteorological and hydrological droughts revealed that among the 24 middle-sized watersheds of the Han River basin, 11 watersheds had bidirectional causality, and the other 13 watersheds had one-directional causality. This study also confirmed that there were large correlations between the two drought types when 12 of the 13 watersheds with one-directional causality had a lag time of 4 months and the remaining watershed had a delay time of 7 months. The complexity of the interaction between different droughts was confirmed through adjustments of key parameters, such as the embedding dimension, time delay, correlation dimension, and Lyapunov exponent. The approach proposed in this study made it possible to analyze the nonlinear dynamic characteristics of drought propagation, which have not been analyzed in previous studies.

Granger Causality Model of Retained Earnings and Financial Performance of Non-Financial Firms Listed on the Nairobi Securities Exchange (NSE), Kenya

Non-financial firms are central to economic development of nations, producing goods and services and alleviating unemployment by creating numerous job opportunities. Despite this potential inherent in non-financial firms, evidence shows that the non-financial firms listed on the Nairobi Securities Exchange (NSE) experience challenges in their financial performance, which lowers their capacity to invest. Although retained earnings have been used as a source of funding among listed non-financial firms, there is a paucity of research on the predictive power between retained earnings and the financial performance of these firms. Therefore, this paper focuses on addressing this paucity by modeling Granger causality between retained earnings and financial performance measured through Return on Assets (ROA) of non-financial firms listed on the NSE. The Wald tests revealed that the financial performance of non-financial firms Granger-causes retained earnings, but retained earnings do not Granger-cause financial performance. The conclusion drawn from these findings is that financial performance of non-financial firms listed on the NSE allows forecasting of future retained earnings. However, future research should leverage emerging advances like Network Granger causality to determine whether bidirectional Granger causality is viable between the two variables.

Decoupling Growth and Pollution: The Interplay of Globalization, Energy, Economy, Finance, and Environmental Quality in SCO Countries

The study aims to examine how globalization, energy consumption, economic growth, and financial development affect environmental quality in SCO member countries. The data collected spans from 1990 to 2019. We conducted a stationarity test and analyzed the long-term relationships using fully modified OLS. Our results show that an increase in energy consumption, economic growth, and financial development leads to higher CO2 emissions, thus reducing environmental quality. On the other hand, globalization was found to reduce CO2 emissions for the country. Additionally, D.H. panel causality test revealed bi-directional causality between environmental quality and the variables used in our analysis. Evidently these findings are crucial for formulating effective policy recommendations aimed at improving environmental quality.

The role of private sector investment in agriculture: A catalyst for sustainable development in Asia

AbstractThe agricultural sector is a crucial driver for sustainable development in many countries, as it directly or indirectly contributes to various United Nations Sustainable Development Goals. However, this sector requires increasing financial investment to rejuvenate and modernise production processes. This study investigates the impact of private sector investment on agricultural production across selected Asian countries from 2001Q1 to 2020Q4. The results of the Driscoll‐Kraay regression and the method of moments quantile regression reveal that private agricultural investment positively affects agricultural production. The findings indicate positive contributions from agricultural aid, domestic credit, and rural population, whereas remittances negatively affect agricultural production. The Dumitrescu‐Hurlin panel causality test results establish bidirectional causality between farm production and its determinants (private agricultural investment, agricultural aid, domestic credit, remittances, and the rural population). Based on these findings, we recommend that policymakers and governments incentivise and facilitate private agricultural investment to drive sustainable development. This strategy could boost agricultural productivity and enhance a more resilient agricultural system capable of withstanding environmental challenges while improving farmers' incomes and livelihoods.

Is the movement of the INR/USD Exchange Rate and the Indian Stock Market Linked? Fresh Evidence

Dollar exchange rate and Indian stock market are leading economic indicators. The present study investigates the relationship between the two economic indicators during the period April 2005 to December 2019. Analysis of Johansen cointegration test reveals that positive long-run cointegrating relationship exists between the variables. The vector error correction mechanism shows that INR/USD exchange rate influences the Indian stock prices negatively in the short-run. The study also observes the presence of bidirectional causality between the variables in the short-run. The variance decomposition analysis further reveals that the Indian stock market is driven to considerable extent by innovations in INR/USD exchange rate. The close relationship that the study found between INR/USD exchange rate and Indian stock market will be an important factor in the decision making of both individual and institutional investors. Furthermore, the study recommends the Indian government to adopt a cautious approach in implementing the foreign currency exchange rate policies

The dynamic relationships between oil products consumption and economic growth in Saudi Arabia: Using ARDL cointegration and Toda-Yamamoto Granger causality analysis

The purpose of this study is to investigate the short-run and long-run relationship between liquefied petroleum gas Consumption (LPGC), natural gas consumption (NGC), other refined products consumption (ORPC), carbon dioxide emissions (CO2), and gross domestic product (GDP) in Saudi Arabia, from 1970 to 2021. To study the link between energy consumption and economic growth and its role in this relationship, we use an autoregressive distributed lag (ARDL) bounds-testing technique of cointegration. The research findings revealed the development of a cointegrating association among all the variables. The anticipated results provide more evidence that a long-run link exists between the drivers of economic development and its regressors. The empirical estimation suggests an LPGC effect that is both beneficial and statistically significant on economic growth. A positive correlation exists between energy consumption and GDP growth. Using the Toda-Yamamoto Granger Causality approach, the causality test reveals a unidirectional causal relationship between the consumption of liquified petroleum and GDP, and between the consumption of natural gas and other refined products. In addition, there is bidirectional causality between GDP and other refined products. Consumption of natural gas and carbon dioxide emissions both have a neutral causal effect on economic growth. In the short run, NGC, ORPC, and CO2 have a positive effect on GDP. The KSA energy policy, actively engaged in slowing CO2 while preserving energy consumption, will significantly benefit from the conclusions of this research. Thus, policymakers should consider how to make LPGC, NGC, and ORPC more prudent and effective, particularly in the energy sector. The government of Saudi Arabia also needs to centralize the renewable energy sector.

Bidirectional causality between idiopathic sudden sensorineural hearing loss and depression: a Mendelian randomization study

Idiopathic Sudden Sensorineural Hearing Loss (ISSHL) is a sudden onset, unexplained sensorineural hearing loss. Depression is a common mental disorder and a leading cause of disability. Here, We used a two-sample Mendelian randomization approach using pooled statistics from genome-wide association studies of ISSHL (1491 cases, 196,592 controls) and depression (23,424 cases, 192,220 controls) in European populations. This study investigated the bidirectional relationship between single nucleotide polymorphisms associated with depression and ISSHL using inverse variance weighting.Additional sensitivity analyses, such as Mendelian randomization-Egger (MR-Egger), weighted median estimates, and leave-one-out analysis, were performed to assess the reliability of the findings. Significant causal association between genetic susceptibility to ISSHL and depression in a random-effects IVW approach (OR = 1.037, 95% CI = 1.004–1.072, P = 0.030). In contrast, genetic depression was not risk factors for ISSHL (OR = 1.134, 95% CI = 0.871–1.475, P = 0.350). After validation by different MR methods and the sensitivity analysis, all of the above results are consistent. The evidence we have gathered suggests a causal relationship between ISSHL and depression. The presence of the former induces or further exacerbates the latter, whereas a similar situation does not exist when the latter is an influencing factor.

Causal associations between psoriasis, eczema, urticaria, and mental illness: A bidirectional Mendelian randomization study of the European population.

Observational studies have reported a relationship between multiple common dermatoses and mental illness. To assess the potential bidirectional causality between 3 skin disorders (psoriasis, eczema, and urticaria) and 4 psychiatric disorders (bipolar disorder, schizophrenia, major depressive disorder, and anxiety) in the European population, we used Mendelian randomization (MR) analysis, which provides definitive evidence for causal inference. Eligible single nucleotide polymorphisms were screened for dermatological and psychiatric disorders using a genome-wide association study database. We conducted bidirectional, 2-sample MR analysis using instrumental variables related to psoriasis, eczema, and urticaria as exposure factors, and bipolar disorder, schizophrenia, major depression, and anxiety as outcomes. Reverse MR analysis with bipolar disorder, schizophrenia, major depression, and anxiety as exposure and psoriasis, eczema, and urticaria as outcomes were also performed, and the causality was analyzed using inverse-variance weighting (IVW), MR-Egger, and weighted median methods. To thoroughly assess causality, sensitivity analyses were conducted using the IVW, MR-PRESSO, and MR-Egger methods. The results showed that bipolar disorder increased the incidence of psoriasis (odds ratio = 1.271, 95% confidence interval = 1.003-1.612, P = .047), heterogeneity test with Cochran Q test in the IVW showed P value > .05, (P = .302), the MR-Pleiotropy and MR-PRESSO (outlier methods) in the multiplicity test showed P value > .05, (P = .694; P = .441), and MR-Pleiotropy evidence showed no apparent intercept (intercept = -0.060; SE = 0.139; P = .694). Major depression increased the risk of eczema (odds ratio = 1.002, 95% confidence interval = 1.000-1.004, P = .024), heterogeneity test showed P value > .05, (P = .328), multiplicity detection showed P value > .05, (P = .572; P = .340), and MR-Pleiotropy evidence showed no apparent intercept (intercept = -0.099; SE = 0.162; P = .572). Sensitivity analyses of the above results were reliable, and no heterogeneity or multiplicity was found. This study demonstrated a statistically significant causality between bipolar disorder and psoriasis, major depression, and eczema in a European population, which could provide important information for physicians in the clinical management of common skin conditions.

Do green finance and digital technology matter for sustainable agricultural development? Insights from sub-Saharan Africa

Sustainable agricultural progress is one of the world’s greatest challenges in the twenty-first century as the global population is estimated to rise to over nine billion by 2050. Over the years, the Food and Agricultural Organization (FAO) and the African Union (AU) have sought prosperous African Policies based on sustainable agriculture and inclusive growth. Additionally, the AU has adopted the Comprehensive African Agricultural Development Programme (CAADP) policy framework. Given the growing need for innovative policies and studies to reduce the negative environmental effects of agricultural development in Africa, this paper investigates the significance of green finance and digital technologies on green agricultural growth in sub-Saharan Africa (SSA) from 2003 to 2018. Analysis of panel co-integration estimates indicates all variables are integrated. Using the panel-corrected standard errors estimator for long-run equilibrium co-integration assessment, the outcomes indicate mitigated green finance (MGF), internet and mobile phone use (IMU), as well as sustainable energy utilization (RE), individually and collectively exert a positive effect on agriculture, forestry and fishing value added (AVA). Additionally, panel causality estimates indicate (i) a bi-directional causality between MGF and AVA. (ii) A uni-directional causality running from IMU towards AVA without any rebound effect. For policy insights, the AU could urge member states to implement macro-policies to increase agricultural green credit to sustain food production and employment generation. Similarly, the FAO and AU could provide technical support in digital agricultural research and value chains towards ensuring sustainable agriculture development in SSA.

Examining the relationship between exports and economic growth in Türkiye: Fourier Toda-Yamamoto Granger causality test

This study aims to investigate the causal relationship between exports and economic growth in Türkiye from 2016:1 to 2023:12, focusing on the validity of the export-led growth hypothesis. The Fourier Toda-Yamamoto Granger Causality Test created by Nazlıoğlu, Gormus and Soytas (2016) was used with variables including total exports and industrial production index derived from monthly data. The data suggest a bidirectional causation between the two variables, indicating that each one is the cause of the other. The export-led growth hypothesis is confirmed in Türkiye for the relevant timeframes. The results of this study align closely with existing research on the topic compared to other studies, further suggesting that decreasing the reliance on imported intermediate items in Turkish export products will enhance the direct connection between exports and economic growth.

Sustainable development through green transition in EU countries: New evidence from panel quantile regression

Sustainable development addresses global challenges by promoting practices that balance economic, social, and environmental considerations. Key factors include the shifting to green energy and the integrating of green technology in the sustainable development process. This study investigates the heterogenous effects of green technology development, green energy, R&D expenditures, FDI, economic growth, and urbanization on CO2 emissions in 25 European Union (EU) countries using panel quantile regression over the period 2000–2021. The results, based on panel quantile regression, indicate that green energy decreases CO2 emissions from the 10th to the 90th quantiles, while green technology development increases CO2 emissions at the lower quantiles (10th to 60th) and then turns negative. The robustness of the fixed effect model also confirms the findings of the study. Additionally, panel causality tests indicate no causal link between green technology development and CO2 emissions, but there is bidirectional causality between green energy and CO2 emissions. Therefore, the findings highlight that policymakers should thoroughly evaluate measures and strategies to encourage the development of green technologies and green energy sources to reduce high levels of CO2 emissions. One strategy is to provide financial aid and support technological advances to produce green energy at reduced costs.

Climate policy uncertainty and energy impacts on trade openness and foreign direct investment in the United States: Evidence from the RALS co‐integration test

AbstractClimate change is becoming an increasingly pressing global issue, and understanding how climate policy uncertainty affects trade openness and foreign direct investment is crucial. This study provides contemporary insights into this complex relationship, particularly in the context of the United States, which is a major player in global trade and investment. The study employed a monthly dataset spanning from January 1990M01 to December 2020M12. Co‐integration exists between all the variables specified by employing Residual Augmented Least Squares (RALS‐EG), climate policy uncertainty, and fossil fuel consumption adverse influence upon trade openness and foreign direct investment, economic growth, and renewable energy consumption positive impact upon trade openness and foreign direct investment via the use of fully modified ordinary least square (FMOLS), and Dynamic Ordinary Least Squares (DOLS). The Fourier Toda‐Yamamoto causality reveals that climate policy uncertainty, economic growth, renewable energy, and trade openness exhibit bidirectional causality, while fossil fuels exhibit unidirectional causality. Based on the findings, policymakers should prioritize reducing climate policy uncertainty to create a more stable environment for trade and foreign direct investment (FDI). Clear and consistent climate policies can mitigate the negative impact of uncertainty on trade openness and FDI.

Relationship between Financial Development and Economic Growth: Evidence from 12 SADC Countries

Purpose: The purpose of this study was to examine the causal relationship between financial development and economic growth in 12 SADC countries for the period 2008-2020. Materials and Methods: The study utilized panel data from 12 SADC member states for the period 2008-2020. This dataset was compiled from the World Bank database, Penn tables, and National Bureau of Statistics websites for the member states. The study employed the Autoregressive Distributed Lag Model (ARDL) to estimate the causal relationship between financial development and economic growth. Findings: The empirical results show that there is bi-directional causality between financial development and economic growth in the SADC region. The findings also suggest that while financial development positively correlates with economic growth in the long run, the short-run effects may vary, with factors such as physical capital accumulation and government expenditure playing significant roles. Trade openness, life expectancy and population growth were also found to have implications for economic growth in the SADC region, highlighting the complex nature of development dynamics. Implications to Theory, Practice and Policy: The presence of bidirectional causality between financial development and economic growth calls for coordinated economic and financial policies as both variables mutually influence each other's dynamics.

Geopolitical risks and tourism industry interactions: Evidence from tokens and equity markets

Geopolitical risk can have an impact on investment behavior and rates of return. We explore the time-varying relation between the daily geopolitical risks index (GPRD) and tourism market. We use tourism tokens (TTI) and tourism equity market indices (WHRL) as proxies of the tourism industry. Results from DCC-GARCH analysis depict weak co-movements between GPRD-TTI and GPRD-WHRL pairs. However, concerning time-varying Granger causality, the GPRD-WHRL pair exhibited longer periods of a significant relationship along with bidirectional causality during the Russia-Ukraine war, whereas the COVID-19 pandemic’s effect was weak in both pairs. Spillovers identified through Q-VAR analysis revealed more pronounced effects of GPRD on each variable during both market events, albeit with a more apparent and stronger influence on WHRL. These findings suggest that the cryptocurrency market may not consistently and effectively incorporate geopolitical risk factors, whereas equity markets demonstrate a greater capacity to capture and respond to such risk factors.

Factor productivity nexus economic growth in Sub-Saharan Africa: Symmetric and asymmetric panel approaches

This study examines the effect and role of total factor productivity with other major determinants on economic growth in the Sub – Saharan Africa(SSA).It employs the data obtained from the World Bank Development Indicators spanning from 1990 to 2022 using panel ARDL, GMM and their extended asymmetric non-linear (NARDL) and (NGMM) models. The NARDL and NGMM are more superior to the counterpart ARDL and GMM symmetric models in the long-run than the short-run estimation, ensuring more efficient and reliable information regarding the effects of productivity on economic growth analysis. Finally, the robust dynamic inter-temporal Granger causality tests show that asymmetrically there is bi-directional causality between the growth rate of an upward movement in total factor productivity and real GDP. There is also bi-directional causality of a downward movement in the growth rate of the terms of trade and real GDP growth rate. The empirical findings of the study are extremely important indicators for sustained economic growth in the SSA region. Hence, this research work recommends that governments should enhance total factor productivity and terms of trade through job-trainning provision and promote trading among themselves as policy tools.