1. Introduction
Two billion people across the planet suffer from nutrient deficiencies. Ironically, even in Sub-Saharan Africa (SSA) where smallholder farm households dominate, numbering 33 million (80% of all the farms) and contribute about 90 percent of food production [
1], households suffer from poor dietary quality and malnutrition [
2,
3]. This could be largely attributed to inadequate and inappropriate diets on account of limited access to food and nutrition information. Consequently, the number of active farmers in recent times has drastically reduced, triggering the failure of the agricultural system to provide foods that allow for nutritious, affordable, diverse, and sustainable diets for all. As a matter of fact, this poses a risk to the future of agriculture, a major driver of African economies. For that reason, food and nutrition security (FNS) in farm households ought to be a serious policy concern [
4] because farmers are important nutrition providers of any community worldwide [
5,
6].
While combining the concepts of food security and good nutrition, FNS recognizes the prominence of key nutrition concerns for achieving food security. According to UNICEF [
7], it is realized when adequate food is available and accessible for and satisfactorily used and utilized by all individuals at all times to live a healthy and active life. In fact, the embedding of “nutrition” between “food” and “security” accentuates that improving nutrition is the ultimate goal. Thus, FNS could aid in addressing the burdens of malnutrition (stunted growth, underweight and obesity) in farm households. Intuitively, malnutrition occurrence is a function of the accessibility and availability of various foods for sustainable and healthy diets all year round [
8,
9,
10]. In support, a myriad of literature documents that there is a significant association between micronutrient adequacy and a varied diet, which eventually results in positive health outcomes [
11,
12,
13,
14,
15,
16,
17]. Impliedly, there may be increased risk of underweight and stunted growth that may even lead to cognitive deficits in the case of a less diversified diet [
18,
19,
20]. Therefore, there is a strong case for ameliorating FNS, especially that this is also one of the most effective approaches to avert hidden hunger sustainably.
In view of the aforementioned, dietary diversification is fundamental. However, increasing agricultural production and access to sufficient calories remains the focus of food security policy and is held as a main solution, particularly in low-income countries. Unfortunately, calories are not all equal. Thus, this school of thought has created a blind spot with respect to the role of nutrition and health information access, which is often overlooked but may be significant for dietary diversification for the rural poor. In agreement, research has demonstrated that increasing social innovation such as informatization (the extent by which society is becoming information-based) is pivotal for driving significant changes in the way we currently live or consume [
21]. Particularly, mobile phone use (used as a concrete example of informatization) is a vibrant and rapidly emerging act that could influence FNS. With the swift growth of the mobile phone coverage lies the great prospects for increasing rural households’ access to useful information on a variety of topics. For instance, the adoption of mobile telephony technologies has significantly improved farmers’ household income [
22,
23], access to information [
24,
25], marketing decision [
26], diversification to high-value crops [
27], greater market participation [
28], agricultural production patterns [
29,
30], and agricultural productivity [
31].
In Zambia, despite the potential of the food and agriculture system to improve FNS especially that it is backed up by government policy, the incidence of malnutrition remains high at about 40 percent [
8]. Particularly in farm households, apart from adults, majority of children suffer from overweight and stunted growth. In addition, consumption is characterized by a mono-diet culture heavily dependent on cereals [
32]. With such a scenario, it cannot be business as usual because malnutrition has various adverse effects, such as immune deficiency [
33], high risk of morbidity and mortality [
34], and suboptimal brain development [
35] which may lead to decreased participants in food production (agriculture).
Given the rising food production and crop production index (
Figure 1), mobile phone use by households could aid in addressing undernourishment through disruption of routines. Evidently, adoption of mobile phones in the country has been very rapid since 2000, and it is extensively used as a platform for communication and information access even by poor farm households in remote rural locations. Therefore, since information access enhances awareness [
36], empowering individuals to ‘switch off the autopilot mode’ (observe and change previous unconscious habits), mobile phone adoption holds the potential to diminish unsustainable and unconscious dietary choices [
37]—by augmenting income [
31] and increasing information access frequency [
38] which could smooth food accessibility, availability, and use. Although seemingly simple, food choice is among the most frequent and complex human behavior. Thus, new insights, particularly the realization that much decision making about diet occurs at a non-conscious level (probably play a more important role in food-related behavior as indicated by Köster [
37]), should lead to a rethinking of the role information access plays. Ultimately, it is such intuitive reasoning that will provide a basis for thorough understanding on how to improve FNS in farm households.
While a few scholars have abstractly examined how the use of the mobile phones could impact on welfare dimensions such as food security, empirical evidence on FNS is limited and not cogent to warrant the much needed policy action. For instance, discourse by Thomas [
40] and Quisumbing and Maluccio [
41] reveal that women tend to do better than their counterparts in dietary diversity without empirical evaluation as to whether improvement in FNS is realized. To begin to fill this gap, this study aims at answering the following questions: (i) Can mobile phones possibly have an effect on dietary diversity, a measure of FNS? (ii) How can mobile phones improve farm households’ FNS? Comprehension of such mechanism is essential especially against the background of United Nations’ vision 2030 as the purview is beyond a narrow category of economic development indicators.
Consequently, the study adds value to the literature in three aspects. First, we analyze informatization effects on FNS using robust econometrics approaches which correct for biases from endogeneity and selection bias. Unlike previous studies, we provide a discourse on how mobile phone use by farm households can translate to improved FNS. In the interest of adequate policy formulation, this is useful and obligatory because food is a very basic need for all. Second, we go beyond assessing associations by also quantifying the increased dietary diversity and quality levels in both male-headed and female-headed households and what it would be had non-adopting households adopted. This is distinctly fundamental under the sustainable development goals (SDGs) framework which advocates for the elimination of malnutrition and world hunger in all forms by 2030 and safeguard access to abundant and nutritious food for all. Finally, the study indirectly lobbies for the nutrition enhancement in farm households especially that the welfare (dietary diversity and quality) of the most important contributors of nutrition worldwide (farm households) is at the core of the investigation. Since farm households’ well-being is linked to agriculture’s success, analysis in the present study has significant policy implication for the sustainability of food production.
2. Materials and Methods
2.1. Data
The empirical analysis is based on the data extracted from a household survey conducted in 2018 in central Zambia where farm households significantly contribute to the national basket. The survey was a baseline study for a project envisioned to empower farm households through the introduction of mobile phone-based technologies for welfare information searching. The primary objective of the project is to promote and contribute to the four pillars of sustainability—social, economic, environmental, and human. The authors are not directly or indirectly linked to the project.
The area under study is covered by at least one mobile network operator which also offers mobile money services, weather forecasts updates, job alerts, and internet services. Farm households in these camps grow maize as their primary crop, in addition to beans, groundnuts, millet, cassava, cotton, sorghum, sweet potato, and tobacco. Dairy and fish farming are also prevalent. The area is typical of the rural African setup and as such most of the food consumed is from their produce or derived from hunting. Household income is from sales of their produce and off-farm employment highly unlikely. The majority of households residing far from markets rarely visit the market centers except during sale of their produce. Such visits are also an opportunity for purchasing of foods which are not commonly consumed.
Four different ways of determining a sample size are identified by Israel [
42] and Singh and Masuku [
43]—carrying out a census for finite and small populations, using tested and published tables, imitating sample sizes of other related or similar studies, and using determined formulae to calculate a sample size. By imitating sample size used in similar/related studies [
44,
45,
46], we used a two-stage sampling procedure to select households for the study. In the first stage, three agricultural camps (Fiwila, Lweo, and Nshinso) in Mkushi district were randomly selected out of 22. Then, a random selection of 201 farm households was performed using the list from the Ministry of Agriculture. Fortunately, all the selected households responded positively and an adult household head was the source of information.
A structured questionnaire, constructed using standard layouts for agricultural household surveys [
47], was used for data collection which took five months (July–November 2018). A pilot study was also done in order to pre-test suitability, validity, and applicability. Details regarding ethical approval of the study can be found in Mwalupaso et al. [
48]. The instrument focused on crop production, income, nutrition, and other socio-demographic details. In addition, food types consumed within a given period was explicitly asked in order to accurately understand farm households’ consumption pattern. Like Mwalupaso et al. [
49], measurement error was minimized via use of trained enumerators, and pre-testing in the local setting.
2.2. Variable Selection and Measurement
2.2.1. Key Explanatory Variable
Mobile phone use (MPuse) is our key explanatory variable. It is captured through a dummy where 1 = households who owned and used mobile phones for information access during the survey year and 0 otherwise. Such measurement of mobile phone use was employed in a recent study by Sekabira and Qaim [
50]. This variable is also the treatment variable upon which treatment effects are calculated.
2.2.2. Outcome Variables
Dietary diversity and quality are the outcome variables of interest which are measures of food consumption. They are based on food access and consumption patterns [
50,
51,
52,
53,
54] and the household dietary diversity (HDD) scores which are a count of the different groups of food consumed over a specific time are used. To adequately evaluate whether informatization matters in enhancing FNS of farm households, a 7-day food consumption recall with 12 foods is constructed to calculate the HDD scores. The foods considered are: cereals (tubers and white roots); vegetables; fruits; poultry and meat; eggs; fish; legumes, pulses and nuts; milk and milk products; oils and fats; honey and sugar; and spices, beverages, and condiments. Regarding dietary quality (diversified and healthy diet), 9 food groups (healthy foods) are considered because HDDS is not necessarily a good indicator of dietary quality when all 12 foods are incorporated [
50]. Thus, we exclude three groups (oils and fats, honey and sugar, and spices, beverages, and condiments) which are calorie dense but have little contribution to micronutrient consumption [
55]. Tentatively, 12 and 9 food groups portray dietary diversity and quality respectively as measures of FNS.
In addition, household income in Zambian kwacha (ZMK) is another outcome variable in the endogenous switching regression (ESR) to understand the underlying mechanism of the impact of mobile phones on FNS.
Similarly, information access frequency, an outcome variable in ESR, is captured through the number of times a household accessed nutrition and health information within a week during the survey year.
2.3. Analytical Framework and Empirical Strategy
The ordinary least square regression (OLS) is adopted to model the influence of the mobile phone adoption on dietary diversity and quality whereas ESR is applied to understand the causal impact. All statistics were implemented in stata (version 14; Stata Corporation, College Station, TX, USA).
Two categories are defined to satisfactorily assess the difference in dietary diversity between gender, i.e., female-headed (FHHs) and male-headed households (MHHs). FHHs consist one of the following: (i) women in polygamous marriages recognized as household head given that their spouse is absent for a considerable portion of time; (ii) they are unmarried and; (iii) those in monogamous marriage, but the husband is absent for more than six months. MHHs capture single and married men who are acknowledged as household head.
2.3.1. Influence of the Mobile Phone Use on Dietary Diversity and Quality
OLS was applied to determine the effect of mobile phone adoption on dietary diversity and quality. The OLS is specified as follows:
where
is the outcome variable representing dietary diversity and quality,
is a vector of parameters to be estimated,
is a vector of factors affecting dietary diversity and quality,
is the coefficient of MP use, and
is the error term for the OLS.
However, mobile phone use is potentially endogenous. Therefore, in the interest of robust estimates, we derived a matched sample through “1-to-1 nearest neighbor matching without replacement” using propensity score matching (PSM) technique. This implies that each adopter was matched with their comparable non-adopter by means of the propensity score or probability (
) of receiving treatment (
) conditional on covariates (
). The major advantage of this approach is that it imposes a region of common support, thereby controlling for biases emanating from observed variables [
56,
57].
2.3.2. Modeling Possible Mechanisms
The impact of mobile phones on dietary diversity is less straightforward because it may evolve through several avenues, possibly including frequency of nutrition and health information access, and income gains. In an attempt to meticulously identify causal pathways, ESR is applied to gain further insights into possible mechanisms.
The choice to adopt mobile phones and its implication on dietary diversity can be modeled in a two-stage treatment, although we adopt a simultaneous estimation procedure (an efficient procedure) developed by Lokshin and Sajaia [
58] that uses full information maximum likelihood (FIML) method. In the first stage of ESR, a dichotomous choice criterion function is modeled and estimated using a probit model. In view of the expected benefits, households evaluate whether or not to adopt mobile phones for information access. This is most likely done on the basis of information access options and other socioeconomic factors. The expected utility of adoption is compared to that of non-adoption because only when the former is greater than the latter will a household adopt. The Probit model can be written in simplified form as:
where
is not observable, but we observe
, a binary indicator variable that equals 1 if a household adopts mobile phone use and 0 otherwise,
includes a variety of household and farm characteristics,
is a vector of parameters to be estimated, and
is a random error term with mean zero and variance
.
In the second stage, two regime equations can be specified explaining the relationship between the outcome variables (dietary diversity, information access and income) and technology adoption (mobile phone use) based on the results of the estimated criterion function. This is done with selectivity correction and specified for each regime as:
where
X represents a vector of covariates, and
is a vector of parameters to be estimated.
Using ordinary least squares (OLS), the estimation of
and
might lead to biased estimates, since conditional on the criterion function, the expected values of the error terms (
and
), are non-zero. In as much as the variables in
and X′ can overlap, at least one variable in
must not appear in X′ to achieve proper identification. Therefore, the selection criterion is estimated based on one or more instruments plus all exogenous variables specified in the regime equations. The error terms (
,
) are assumed to follow a tri-variate normal distribution with zero mean and a non-singular covariance matrix specified as [
59]:
where
,
, and
are the variances, assumed to be one [
60] of the error terms
,
, and
, respectively.
is the covariance of
and
;
is the covariance of
and
; and
is the covariance of
and
.
Under these assumptions, the truncated error terms
and
are:
where
and
are the inverse Mills ratios (IMRs) evaluated at
while
and
are the probability density and cumulative distribution functions of the standard normal distribution, respectively.
To derive the average treatment effects (average treatment effect on the treated (ATT) and untreated (ATU)), the expected outcome values of the adopters and non-adopters in actual and counterfactual scenarios can be calculated and compared. The ESR framework permits the computation of the expected values in the real and hypothetical scenarios [
58] defined as follows:
Adopters with adoption (observed):
Adopters had they decided not to adopt (counterfactual):
Non-adopters had they decided to adopt (Counterfactual):
Non-adopters without adoption (Observed):
Following Di Falco et al. [
61] and Carter and Milon [
62], ATT and ATU are computed as follows:
2.3.3. Determinants of Mobile Phone Adoption for Information Access
The Probit function was employed in evaluating the factors affecting mobile phone adoption. However, biased estimates are expected due to potential selection bias and endogeneity. For robust estimates, endogeneity was also tested using a control function (CF) technique. The grounds for selecting this procedure are: (i) regardless of weak instruments, it is efficient, (ii) unlike other instrumental variable (IV) approaches, Wooldridge [
63] proposes that it is exceptionally efficient for binary endogenous variables. For the two-stage endogeneity test, estimating exogenous variables (control variables and instruments satisfying orthogonality condition of IVs) that influence mobile phone ownership with the aid of a Probit function specified in Equation (12) makes up the first stage. Generalized residuals (GR) were then calculated.
The second stage of the CF involved the actual estimation of the outcome variable of interest (mobile phone use against mobile phone ownership and other covariates). To ensure estimations are exempt from biases, GR together with other control variables, are included in this stage [
64].
where
is a dummy (1 = owns mobile phone and 0 otherwise),
is also a dummy as already established,
,
, and
are parameters to be estimated,
and
are vector of factors affecting mobile phone ownership and use respectively,
and
are error terms.
4. Conclusions
In developing countries, particularly among farm households, malnutrition is a problem of significant magnitude posing a threat to the sustainability of agriculture and food systems. Thus, improvement in food and nutrition security is paramount. To this end, diversifying diets and increased access to information is widely perceived as a solution. However, empirical evidence regarding the link of the latter with households’ dietary diversity is limited. In view of the rapid spread of mobile phones in rural Sub-Saharan Africa, which has offered the possibility for increased information access, we investigate whether informatization (mobile phone use used as a concrete example) has an association with improved dietary diversity and quality.
Our results indicate that mobile phone use is positively associated with dietary diversity and quality. In fact our results reveal that both MHHs and FHHs are worse off without mobile phone adoption, leading to our conclusion that informatization does matter in ameliorating food and nutrition security in farm households. With such findings, we have reasons to be optimistic despite the burdens of malnutrition facing farm households today. Therefore, in an attempt to scale up mobile phone use among farm households, we strongly recommend policy directed at empowering households with mobile phone ownership, making mobile phone use easier and inexpensive and establishing reliable information centers addressing food and nutrition security. This is consonant with sustainable development goals and has great potential to realize sustainable development especially that ‘a healthy farm household is a healthy farm’.
Finally, our study has important implications for future research. First, there are other broader benefits like positive environmental externalities that were not analyzed in the present study. Future studies looking beyond farm household level with broader implications would be useful. Second, informatization depends on households’ capacity to adapt to local circumstances and thus impacts may change over time. This was not examined in this study owing to the use of cross-sectional data. Therefore, use of panel data to appropriately understand the impact dynamics in terms of how informatization influences dietary patterns choices over time is strongly encouraged.