Papers by Jouni K Juntunen
Collective and citizen-driven activities for energy transition have been thriving globally in rec... more Collective and citizen-driven activities for energy transition have been thriving globally in recent decades. Community energy innovation (CEI) developed through hands-on engagement with materials has garnered increasing attention from the interdisciplinary energy research community. The recent scholarly discussion has highlighted the role of materiality and its relation to collective agency, inclusion, and approaches to participation. Accordingly, paying attention to materiality in CEI can clarify sociotechnical aspects of energy innovation which have been commonly understood through either solely a social or technical view. Furthermore, fostering citizens' take-up of renewable energy in more democratic ways is a prerequisite for accelerating the energy transition and is arguably best done via material, hands-on engagement. However, the focus on materiality, particularly hands-on material engagement, in research on community energy appears to be fragmented. Therefore, we conducted a systematic literature review to better understand how researchers understand and approach materiality and material engagement in CEI. The results of analyzing 36 papers highlight that materiality in CEI has been studied in interdisciplinary fields through diverse methods, and we identify four types of networks in which such innovation emerges. We also identify geographically dispersed and Do-It-Yourself enthusiast-led energy innovations which go beyond the existing understanding of CEI. More importantly, a network may change over time and place because of the configurational material nature of decentralized smallscale renewable energy technologies. However, studying materially-engaged CEI needs further efforts to integrate empirical data more centrally with the existing knowledge base and concretely define how materiality plays out in collective energy innovation.
Renewable and Sustainable Energy Reviews, 2021
Autonomy is often cited as a key aspect of energy systems. Previous academic literature on energy... more Autonomy is often cited as a key aspect of energy systems. Previous academic literature on energy autonomy has predominantly approached it from a technological perspective, and conceptualized it as self-sufficiency of energy production. In addition to self-sufficiency, autonomous energy users and communities often aim to create energy systems that treat different stakeholders as equals, with a balanced distribution of costs and benefits. This paper has two aims. First, it aims to clarify the concept of 'energy autonomy'. Second, it aims to provide an overview of existing literature addressing energy autonomy, identifying relevant publications and publication outlets, as well as main research themes and activities. The results, based on a systematic review of 71 peer-reviewed academic articles, show that energy autonomy research has increased in the last twenty years. The results also show how existing literature has understood, and used, the concept of energy autonomy in varying ways. Furthermore, the paper reveals how motivations, technologies, and scales differ in energy autonomy projects. While the aim of reaching energy autonomy is often motivated by economic and/or social reasons, these aspects are nevertheless rarely discussed in academic literature as the predominant focus tends to be on technological issues and self-sufficiency. The paper concludes with energy policy implications and avenues for future research.
Journal of International Business Studies, 2021
The global energy system has a long way to go to meet international climate goals, and significan... more The global energy system has a long way to go to meet international climate goals, and significant investment in renewable energy is required to accelerate the energy transition (IRENA, 2016, 2019). We examine how firm-and country-specific conditions in the electric utility sector impact foreign direct investment (FDI) in renewables. Using a unique dataset of 289 greenfield investments by 17 multinational energy utilities, we employ a fuzzy set qualitative comparative analysis (fsQCA) that yields five causal configurations leading to FDI in renewables and four configurations leading to investment in non-renewables. Our results indicate that private MNEs are at the forefront of investment in renewables, and while state-owned MNEs (SOMNEs) do invest in them, they tend to follow strategies that are less risky compared to private MNEs and more responsive to host-country incentives. Our analysis suggests that for private MNEs, international experience is strongly associated with investment in renewables, while for SOMNEs it is associated with investment in non-renewables. Further, we also identify instances where MNEs contribute simultaneously to a 'race to the top' and a 'race to the bottom' by investing in both renewables and non-renewables in different markets, thereby reducing the pace of the energy transition. Journal of International Business Studies (2021).
Environmental Innovation and Societal Transitions, 2020
To date, a major portion of sustainability transition research has relied on retrospective method... more To date, a major portion of sustainability transition research has relied on retrospective methods to generate encompassing macro-level views of transitions. However, such methods may have considerable impacts on the insights generated in the study of intermediation, action and agency by actors on the micro-level of transitions. In this article, we compare retrospective interviews and real-time ethnography to understand how they portray micro-level transition processes and intermediation. The empirical context of our study is energy retrofitting, which we use to illustrate three structural and three process aspects that distinguish the findings from retrospective interviewing and real-time ethnography. Ethnographic methods can provide significant new detail on the uncertainty and complexity of micro-level transition processes while interviews facilitate cross-case comparison and understanding of commonalities in micro-level transition intermediation processes better.
Renewable and Sustainable Energy Reviews, 2019
Energy retrofits in households are an important means of reducing energy consumption and mitigati... more Energy retrofits in households are an important means of reducing energy consumption and mitigating climate change. However, energy retrofit rates have generally been lower than expected. As a key reason behind non-adoption, the complexity of energy retrofits can be challenging for adopters to handle. In this article, we study how suppliers and retrofit adopters seek to manage the complexity of an energy retrofit purchase. Using interview and mystery shopping data, the article analyses how the complexity is managed through a variety of complexity management devices (CMD) and complexity management strategies (CMS). We identify four complexity management devices, concretizations that help deal with energy retrofit complexity: characterisations, projections, comparisons and references. In addition, we identify four complexity management strategies for managing complexity: pre-exposure, choice simplification, outsourcing and championing. The contribution of the study is in highlighting the role of complexity management in energy retrofits and how CMDs and CMSs are involved in structuring energy retrofit offerings, business models and energy information. This, in turn, provides impetus for developing measures to ease the complexity of adoption.
Energy Policy, 2019
Comprehensive energy retrofits by households and housing companies have been recognised as import... more Comprehensive energy retrofits by households and housing companies have been recognised as important means for emission reductions. However, the diffusion of comprehensive energy retrofits has not been as fluent as expected. In this article, we study the Finnish energy retrofit market and comprehensive energy retrofit acquisition process through participant observation and interview methods in order to better understand the work that housing companies, as potential adopters, must carry out. The results of our study suggest that to operate in the current market, adopters must expend a considerable amount of effort in finding market actors, understanding the offerings and coming to grips with what kind of energy system would be ideal for their site. Only a handful of market actors are able to help adopters in this work and even these were difficult to locate due to their position in the energy retrofit market ecology. The study indicates that future policy should foster matchmaking between potential adopters and energy counselling services and support tighter collaboration between public and private energy sector actors.
Journal of Product Innovation Management, 2018
Sustainability is a key driver of innovation for products, services, and business models. Sustain... more Sustainability is a key driver of innovation for products, services, and business models. Sustainability innovations are aimed at improving the environmental, social, and economic performance of the innovated solution. Given the complexity of many sustainability challenges, leading innovators may seek to boost their innovation capacity by tapping into the ideas, knowledge, and expertise of their stakeholders. In doing so they need to consider how many and which stakeholders to integrate into new product development (NPD) processes, and at what stage. This study investigates stakeholder integration strategies associated with high sustainability performance of innovation. Building on the literatures of sustainability innovation and stakeholder integration in the context of NPD, this study developed a configurational model to analyze stakeholder integration strategies. The empirical data consisted of 80 interviews and documents from 13 medium to large companies and their stakeholders in Europe. Using the fsQCA method, it was found that there is not just one effective strategy but three stakeholder integration strategies for high sustainability performance of innovation. The results imply that deep organizational engagement with stakeholders is necessary for the achievement of high performance. Otherwise, the three strategies range from progressive openness, which allows stakeholders to exert a fundamental influence on the sustainability innovation, to limited openness toward stakeholder integration. With the early secondary strategy pointing to progressive openness, companies integrate secondary stakeholders early on and so maximize the influence of different views on the innovation. As to limited openness, companies following the selective strategy limit the number of stakeholder groups in NPD but are indifferent to the timing of these groups’ inputs. Finally, the finetuning strategy is least open to atypical views as it restricts the share of secondary stakeholders and only allows external inputs after the fuzzy front end phase when key decisions regarding the innovation have been made.
Citizen users play important roles in the acceleration phase of energy transitions, during which ... more Citizen users play important roles in the acceleration phase of energy transitions, during which small-scale renewable energy technologies (S-RET) become taken up more widely. From users' perspective, turning the early, and typically slow, proliferation into a more rapid and widespread diffusion requires not only the adoption of S-RET but also the adaptation, adjustment, intermediation and advocacy of S-RETs. These activities become necessary because S-RET face a variety of market, institutional, cultural and environmental conditions in different countries. New Internet-based energy communities have emerged and acted as key user-side transition intermediaries that catalyse these activities by qualifying market information, articulating demand and helping citizen users to reconfigure the standard technology to meet the specificities of different local contexts. In doing so, Internet communities foster an appreciatively critical discourse on technology. Such user intermediation is important in expanding the markets for S-RET beyond that of enthusiasts, environmentalists and other early adopters, to the early majority of adopters who demand more exposure, clearer information and less uncertainty about new technology options.
Research on sustainable practices has attracted increasing interest as a way to understand energy... more Research on sustainable practices has attracted increasing interest as a way to understand energy demand and transitions towards sustainability. In this paper we elaborate on how practice theories can inform the discussion of experimentation. Practice theory suggests that the everyday life of people appears recalcitrant. Practices are robust, resilient and have multiple, historically formed constituents and are thereby difficult to destabilize and change quickly. The making and breaking of links inside and between practices is highlighted, as is the need for enduring, multi-sited change efforts. Practice theory further helps us to better understand the constitution of new, levelled forms of expertise, the distributed nature of experimentation and the enrolment of citizens as active participants in sustainability transitions. We have operationalized and examined these suggestions in a Finnish research project related to climate change mitigation and energy use in detached houses. We report specific modes of experimentation and innovation, including user innovations, and the shared resources of situated expertise, the collective and shared processes of empowerment and the ways in which normality is challenged by ruptures in everyday life. Based on the results, we derive suggestions for effective policy interventions. We also bring forward a set of generic suggestions for more sensitive, appreciative and effective public policies on sustainability transitions and cast experimentation in a particular and partial role in such policies.
Consumers are no longer mere adopters of small-scale renewable energy technologies (S-RETs) such ... more Consumers are no longer mere adopters of small-scale renewable energy technologies (S-RETs) such as solar, pellet and heat-pump technologies. Prosumers create new technology solutions, collaborate with other consumers, and share their ideas, knowledge and inventions with peers in online communities they have formed. These activities by consumers support the proliferation of sustainable energy technology in contexts where institutions and technology characteristics are not yet fully developed for the wide proliferation of S-RET. The issues in the market diffusion of cleaner micro-generation technologies are not limited to " barriers " or " challenges " to top-down diffusion. Given that prosumers do many things to aid the diffusion of S-RET, we investigated how consumer created technology solutions diffused: their existence adds to solution variety, but do others then pick this up? The findings show that 2.7% of the consumer innovations diffused through commercial channels and 8.2% diffused through their straight adoption by peers. A significant share of projects (34.1%) were part of " innovative peer diffusion " adaptations and further modifications carried out among peers. Prosumers' efforts to diffuse their solutions remain low level and indicate directions for platform development by which prosumer solutions may spread more widely.
A B S T R A C T This article addresses the investment gap in renewable energy sources identified ... more A B S T R A C T This article addresses the investment gap in renewable energy sources identified by several authors. Examining the case of a country, Finland, which introduced policy measures to diversify its renewable energy portfolio, we analyse the development of investments in renewable heat and power in response to new policy measures and contextual factors during the downturn period 2009–2013. We investigate investor heterogeneity, i.e., the diversity of logics employed by different types of RES investors. In spite of a severe financial recession, we find an emergence of new sources of investment. Among these new investor types, we find diversity in investment drivers and available options. These include investors mobilized by the feed-in-tariff to seek profitable targets and investors such as real estate owners investing in heat pumps for their own use and benefiting from low interest rates. We find that the diversification of investors supports the diversification in RES sources, and brings in new investors undeterred by the financial downturn. Our findings imply that policy-makers should recognize that the responses to distinct incentives and pressures vary by investor types. This also means that a mix of policies is required to maximize the contribution of different sectors to filling the renewable energy investment gap.
Renewable and Sustainable Energy Reviews, Sep 2015
A widespread adoption of distributed generation (DG) technologies in energy systems can play a ke... more A widespread adoption of distributed generation (DG) technologies in energy systems can play a key role in creating clean, reliable energy and support the targets of emission reduction. A transition from current modes of production to a significant deployment of renewable energy technologies can fundamentally affect the structure of the industry and change the way energy is produced, transmitted and sold. The current paper provides an extended review of the socio-technical configurations of micro-generation based on journal publications and reports during the 21st century. The paper analyses currently existing and missing configurations and discusses technology and policy implications to support proliferation of micro-generation technology and local energy production from renewable sources. The potential for new configurations can be found particularly in heat producing micro-generation with solar heat, heat pumps, and biomass. Developing further the operations and maintenance of distributed generation technologies and business models appears an area that calls for further innovation, and corresponding innovation policy measures. Third party service and community-driven deployment models can aide the proliferation of distributed generation and further innovation therein, justifying the introduction of feed-in-tariffs to attract such models during their early diffusion.
Time use survey data has been used to model household activities beyond market transactions. Acco... more Time use survey data has been used to model household activities beyond market transactions. Accordingly, measures such as the ‘goods intensity of household activities’ and the ‘energy and carbon intensity of household activities’ have been derived. In this paper, we build on this approach by using time use data to model the direct and indirect energy use of households. From this, we present a decomposition analysis of the changes in the embedded and direct energy consumption of Finnish households from 1987 to 2009. Relevant questions that arise include that of whether increases in total energy consumption are due to changes in activity patterns, changes in the energy intensity of activities, or due to demographic changes. Beyond the empirical work, we suggest that time use approaches require a more explicit theorization of time.
The Highways & Byways to Radical Innovation - Design Perspectives, Nov 2014
Theories of innovation, and especially of radical innovation, have often overlooked the innovatio... more Theories of innovation, and especially of radical innovation, have often overlooked the innovation of meanings, especially in its more radical form. In this chapter we will illustrate how this innovation is related to other types of innovation, will discuss its nature and will show that radical innovation of meanings always occur, in every industry, and has the power to shape competition thereafter.
PhD thesis, Oct 2014
In the energy sector, the end-user role is changing from passive consumer to active co provider w... more In the energy sector, the end-user role is changing from passive consumer to active co provider with decentralized technologies. This enables new forms of collaboration and active engagement with technology. This thesis examines energy prosumers' active engagement with renewable micro-generation technologies and draws from and contributes primarily to research on energy consumption, social shaping of technology, and user innovation research. Based on 52 interviews and ethnography on large Finnish online forums conducted during years 2011-2012, this study addresses the following question: What kind of forms of active energy usership emerge with renewable micro-generation?
The key findings demonstrate how homeowners have an evolutionary approach in building and configuring residential energy systems. The trust in new small-scale renewable energy technologies is built gradually and capacity is scaled up along with accumulating trust. New micro-generation technologies tend to become supporting sources besides existing technology and the use of one renewable technology easily leads to the use of other renewable sources later on. The concept of 'domestication pathways' describes this phenomenon. Furthermore, the findings reveal the emergence of new types of energy communities. Traditionally, community energy has been seen as local activity. However, user-run online forums play key role by providing advanced peer support and demonstrate how community energy can take highly dispersed structure and virtual form. These Internet communities support both domestication of micro-generation technology and creative user projects, which range from do-it-yourself copy systems to new inventions spreading out in various ways. The study charted user inventions in heat pump and wood pellet burning systems and found 192 inventions or modifications that improved either efficiency, suitability, usability, maintenance, or price of the micro-generation systems.
The gradual development of domestic energy systems should be recognized in energy policy. Flexibility to adapt to changes is an important factor and it fosters sustainable development pathways for housing energy systems and proliferation of renewable energy generation in households. Regulatory actions can open the existing lock-ins and support hybridization of the systems and the use of various renewable energy sources. Consequently, for the manufacturers hybridization points towards increased importance of modularity and multi-purposing of micro-generation products.
This article compares climate impacts of two heat-pump systems for domestic heating, that is, ene... more This article compares climate impacts of two heat-pump systems for domestic heating, that is, energy consumption for space heating of a residential building. Using a life cycle approach, the study compared the energy use and greenhouse gas (GHG) emissions of direct electric heating, a conventional air-source heat pump, and a novel ground-source air heat pump innovated by a citizen user, to assess whether such user innovation holds benefit. The energy use of the heat pumps was modeled at six temperature intervals based on duration curves of outdoor temperature. Additionally, two heat pump end-of-life scenarios were analyzed. Probabilistic uncertainty analysis was applied using a Monte Carlo simulation. The results indicated that, in ideal conditions, that is, assuming perfect air mixing, the conventional air-source heat pump’s emissions were over 40% lower and the ground-air heat pump’s emissions over 70% lower than in the case of direct electric heating. Although proper handling of the refrigerant is important, total leakage from the retirement of the heat-pump appliance would increase GHG emissions by just 10%. According to the sensitivity analysis, the most influential input parameters are the emission factor related to electricity and the amount of electricity used for heating.
International Journal of Innovation Management, Jan 1, 2015
Users play an increasingly important role in product and service innovation. Finding the right us... more Users play an increasingly important role in product and service innovation. Finding the right users can require substantial search effort. Network searches are increasingly popular in searching for rare lead users. In these searches, implicit and inexact referrals have been
found to comprise a substantial number of network referrals; numbers as high as 70% of the most important referrals to sought people have been reported. To aid handling such referrals during network searches, we explicate their status as intermediate referral types, and how these referral types relate to known search methods. The constraints set by intermediate referrals could potentially be overcome and their potential be capitalized through more extensive method combination in network searches than has been trialed to date. We proceed to offer a proof of concept for such searches through documenting how we ran them in four realworld searches and chart future research avenues.
Keywords: Lead users; user innovation; network search; pyramiding; intermediate refer- rals; implicit referrals; inexact referrals; combinatory search; rare research subjects.
The sociology of consumption uses the domestication framework to examine adaptation processes in ... more The sociology of consumption uses the domestication framework to examine adaptation processes in which technology becomes part of everyday life. This study applies the domestication framework to renewable decentralized energy technologies (DET). Drawing on interviews and Internet material from household and summer-cottage inhabitants using DETs in Finland, the study sheds light on how renewable energy technologies are adapted in local conditions. In such adaptation, multiple domestications are linked and lead to the increasing use of new technologies without a stable final point, a process which can be conceptualized as domestication pathways. Modularity, product multipurposing, and convenient interoperability with other systems are key requirements to enhance the diffusion of renewable energy technologies.
Environmental Research Letters, Sep 23, 2013
The relationship between urban form and greenhouse gas (GHG) emissions has been studied extensive... more The relationship between urban form and greenhouse gas (GHG) emissions has been studied extensively during the last two decades. The prevailing paradigm arising from these studies is that a dense or compact urban form would best enable low-carbon living. However, the vast majority of these studies have actually concentrated on transportation and/or housing energy, whereas a growing number of studies argue that the GHG implications of other consumption should be taken into account and the relationships evaluated. With this two-part study of four different area types in Finland we illustrate the importance of including all the consumption activities into the GHG assessment. Furthermore, we add to the discussion the idea that consumption choices, or lifestyles, and the resulting GHGs are not just a product of the values of individuals but actually tied to the form of the surrounding urbanization: that is, lifestyles are situated. In part I (Heinonen et al 2013 Environ. Res. Lett. 8 025003) we looked into this situation in Finland, showing how the residents of the most urbanized areas bring about the highest GHG emissions due to their higher consumption volumes and the economies-of-scale advantages in the less urbanized areas. In part II here, we concentrate only on the middle-income segment and look for differences in the lifestyles when the budget constraints are equal. Here we also add the variables housing type and motorization into the assessment. The same time-use and private expenditure data as in part I and the same GHG assessment method are used here to maintain high transparency and comparability between the two parts. The results of the study imply that larger family sizes and economies-of-scale effects in the less dense areas offset the advantages of more dense living when the emissions are assessed on per capita basis. Also, at equal income levels the carbon footprints vary surprisingly little due to complementary effects of the majority of low-carbon lifestyle choices. Motorization was still found to increase the emissions, but a similar pattern regarding housing type was not found.
Uploads
Papers by Jouni K Juntunen
The key findings demonstrate how homeowners have an evolutionary approach in building and configuring residential energy systems. The trust in new small-scale renewable energy technologies is built gradually and capacity is scaled up along with accumulating trust. New micro-generation technologies tend to become supporting sources besides existing technology and the use of one renewable technology easily leads to the use of other renewable sources later on. The concept of 'domestication pathways' describes this phenomenon. Furthermore, the findings reveal the emergence of new types of energy communities. Traditionally, community energy has been seen as local activity. However, user-run online forums play key role by providing advanced peer support and demonstrate how community energy can take highly dispersed structure and virtual form. These Internet communities support both domestication of micro-generation technology and creative user projects, which range from do-it-yourself copy systems to new inventions spreading out in various ways. The study charted user inventions in heat pump and wood pellet burning systems and found 192 inventions or modifications that improved either efficiency, suitability, usability, maintenance, or price of the micro-generation systems.
The gradual development of domestic energy systems should be recognized in energy policy. Flexibility to adapt to changes is an important factor and it fosters sustainable development pathways for housing energy systems and proliferation of renewable energy generation in households. Regulatory actions can open the existing lock-ins and support hybridization of the systems and the use of various renewable energy sources. Consequently, for the manufacturers hybridization points towards increased importance of modularity and multi-purposing of micro-generation products.
found to comprise a substantial number of network referrals; numbers as high as 70% of the most important referrals to sought people have been reported. To aid handling such referrals during network searches, we explicate their status as intermediate referral types, and how these referral types relate to known search methods. The constraints set by intermediate referrals could potentially be overcome and their potential be capitalized through more extensive method combination in network searches than has been trialed to date. We proceed to offer a proof of concept for such searches through documenting how we ran them in four realworld searches and chart future research avenues.
Keywords: Lead users; user innovation; network search; pyramiding; intermediate refer- rals; implicit referrals; inexact referrals; combinatory search; rare research subjects.
The key findings demonstrate how homeowners have an evolutionary approach in building and configuring residential energy systems. The trust in new small-scale renewable energy technologies is built gradually and capacity is scaled up along with accumulating trust. New micro-generation technologies tend to become supporting sources besides existing technology and the use of one renewable technology easily leads to the use of other renewable sources later on. The concept of 'domestication pathways' describes this phenomenon. Furthermore, the findings reveal the emergence of new types of energy communities. Traditionally, community energy has been seen as local activity. However, user-run online forums play key role by providing advanced peer support and demonstrate how community energy can take highly dispersed structure and virtual form. These Internet communities support both domestication of micro-generation technology and creative user projects, which range from do-it-yourself copy systems to new inventions spreading out in various ways. The study charted user inventions in heat pump and wood pellet burning systems and found 192 inventions or modifications that improved either efficiency, suitability, usability, maintenance, or price of the micro-generation systems.
The gradual development of domestic energy systems should be recognized in energy policy. Flexibility to adapt to changes is an important factor and it fosters sustainable development pathways for housing energy systems and proliferation of renewable energy generation in households. Regulatory actions can open the existing lock-ins and support hybridization of the systems and the use of various renewable energy sources. Consequently, for the manufacturers hybridization points towards increased importance of modularity and multi-purposing of micro-generation products.
found to comprise a substantial number of network referrals; numbers as high as 70% of the most important referrals to sought people have been reported. To aid handling such referrals during network searches, we explicate their status as intermediate referral types, and how these referral types relate to known search methods. The constraints set by intermediate referrals could potentially be overcome and their potential be capitalized through more extensive method combination in network searches than has been trialed to date. We proceed to offer a proof of concept for such searches through documenting how we ran them in four realworld searches and chart future research avenues.
Keywords: Lead users; user innovation; network search; pyramiding; intermediate refer- rals; implicit referrals; inexact referrals; combinatory search; rare research subjects.
Energy technologies are embedded into socio-technical systems – in which producers, infrastructures, users, consumers, regulators and other intermediaries are all embroiled. A transition from current modes of production to large-scale deployment of renewable energy technologies will fundamentally affect the structure of the industry and change the way energy is produced, transmitted and sold. The energy domain is developing rapidly and new configurations of producing energy are emerging. Configurations of producing renewable energy are becoming multifaceted and clear demarcation lines between centralized and decentralized, grid-connected and off-grid and also producer and consumer have increasingly blurred.
This paper gives an overview of the existing literature on configurations and modes of micro-generation in science and technology studies and business research. Earlier STS research has revealed the wide variety of “modes”, which are social and infrastructural organization through which alternative renewable energy technologies are utilized. The starting point of the study is the socio-technical configuration framing in UK market, which was introduced by Walker and Cass in 2007. Similarly, the configurations have received attention in business research with a focus on value chain and renewable energy business models. The paper develops further the conceptual framework of socio-technical configurations of micro-generation and proposes number of suggestions for future research.