The Learning x Transfer Equation is Wrong!

The Learning x Transfer Equation is Wrong!

The full equation is: Learning x Transfer = Results. When I say it is wrong, I am using the word in the way that the famous statistician, George Box, said "all models are wrong" because they are approximations of reality, "but some are useful." [1] He went on to say:

So the question you need to ask is not "Is the model true?" (it never is) but "Is the model good enough for this particular application?

I have come to the view that the Learning x Transfer Equation is not good enough as a guide to effective training (i.e. formal learning). If the attacks on training and criticisms of its efficacy are anything to go by, I think a more realistic formula will be helpful.

If you're wondering about my choice of the header graphic, it's because I feel like I'm really sticking my neck out with this topic. What follows is not a short article as my aim is to provide a compelling, research-based argument. Please hang in as I'm sure you will find it worthwhile. [All bolded text inside quotes are my added emphasis.]

If you are short of time, or just want to know 'the answer', you can jump to the last section: A New Equation.

This article complements the 'How to Train Your Workforce' podcast episode on training effectiveness. You can access it here: Amazon Music, Apple Podcasts, Google Podcasts, Spotify. David King is an excellent host and I recommend his podcast.

A Mental Model

From my experience, one of the most significant causes of training ineffectiveness is flawed or misleading ‘mental models’ of training and learning. By mental models I mean our internal, simplified (and often simplistic) understandings of how things work in the real world.

The Learning x Transfer = Results Equation is one such model. I used to refer to it as the Training Effectiveness Equation and sometimes wrote it as follows when explaining the importance of application:

Learning x Transfer = Effectiveness

This simple equation has been around, in one form or another, for a long time. For example, in 1985, an article in the Training and Development Journal [2] used the formula:

Learning Experience (LE) x Work Environment (WE) = Results

When I first went into consulting the equation was mostly written as:

Training x Transfer = Results

Over time, 'learning' increasingly replaced 'training' to give us the latest version. One of the reasons for this was the growth of e-learning. Also, I think many vendors saw this as one way of positioning their technology/products as being different from 'traditional training'.

The Learning x Transfer Equation is widely used in our industry although often not in the form of an equation. You have probably seen it as a learning phase followed by a transfer phase. The Training x Transfer version (a training phase followed by a transfer phase) is also still widely used, especially in the research literature.

What the Equation Tells Us

If my memory of algebra serves me correctly, the parts of an equation that are multiplied together are called factors. Using more modern jargon, we refer to Learning and Transfer as 'drivers' of results. In the rest of the article, whenever I refer to these two drivers, I have put the words in capital letters.

Essentially, the Learning x Transfer Equation tells us that the results and therefore effectiveness of training depends on LEARNING being followed by TRANSFER. Both are necessary to the achievement of work performance goals. A lack of TRANSFER gives rise to what is known as the 'transfer gap' (or learning-doing gap).

What I have noticed in many different publications, especially research papers, is that the word training is used when referring to the first part of the equation (e.g. training course or training program). This indicates that LEARNING is what happens 'during training' and TRANSFER is what happens 'after training'.

No alt text provided for this image

Consider the following definitions:

  • "Training transfer refers to the effective application at the workplace of new knowledge, skills, and abilities acquired during a training program..." [3]
  • "Training transfer refers to the workplace application of trained knowledge and skills in a post-training environment." [4]

According to these definitions, "training" is distinct from transfer and does not include application of knowledge/skills in the workplace. As Ragini Chauhan et al put it: "Transfer of training occurs after a training program is completed." [5]

Frequently the word training isn't used, notably if the topic concerns e-learning or blended learning. Instead we just see use of the word 'course' or 'program' when referring to LEARNING.

Another key aspect of the equation is the responsibility associated with the two drivers. Let’s accept that every learner has a responsibility for their own development; then who else is responsible? A 'traditional' perspective is that L&D is responsible for making the LEARNING happen and managers are responsible for ensuring that TRANSFER happens. For example, this statement:

"LE means learning experience... Training and development professionals are responsible for this part of the equation. WE represents the work environment of the learner... Line management must ensure that the environment supports, reinforces and rewards the learner for using the new skills and knowledge." [2]

Four Issues With the Equation

The following issues explain why I have stopped using Learning x Transfer = Results.

1. Transfer is a Poor Metaphor

My first issue is with the word TRANSFER, or rather with how it is interpreted. As mentioned above, many definitions of transfer indicate that learning takes place during training and is then applied in the workplace.

There have been numerous criticisms of this metaphor:

  • "The term transfer itself suggests a simple pattern of learn-it-here, apply-it-there." [6]
  • "Transfer suggests a relatively passive "carrying-over" and deployment of learning from one situation to another..." [7]
  • "Learning is completed in the training session and then, much like luggage transfer, training results are carried over to the workplace." [8]

According to Paul Hager and Phil Hodkinson, "The metaphors [of acquisition and transfer] encourage the common-sense notion of a commodity or substance being literally?moved from one location to another." [9] The individual is basically perceived as a container of knowledge/skill, like the contents of a mental filing cabinet.

If transfer is perceived as simply moving or transporting knowledge/skills from one situation to another, then it is easy to fall into the trap of placing more value on the acquisition of the knowledge/skills than on its application. It is also easy to overlook the dynamics of transfer when new learning is applied at work, i.e. the associated changes in the learner and in the work situation.

As I will clarify later, transfer is a two-way process. Stephen Yelon (a Professor of Educational Psychology) and two colleagues at Michigan State University, provide an excellent analogy from criminal investigations. It is called the law of exchange. According to this principle, a perpetrator inevitably leaves traces at the scene of a crime and takes traces away. There is an interchange of traces. [10] Ironically, in the 2002 film, Murder by Numbers, this exchange principle was described as transference!

2. Learning Involves Transfer

According to the Learning x Transfer Equation, TRANSFER is what happens after LEARNING. But this is not accurate since transfer is an integral part of learning.

According to Robert Haskell: "Transfer of learning is our use of past learning when learning something new and the application of that learning to both similar and new situations." He makes the point that "All learning involves transfer from prior learning to a greater or lesser degree." [11]

Whenever we are in a learning situation (formal or informal), we make sense of the situation by accessing prior learning saved in our long-term memory. The use of prior learning in a new learning situation is called transfer, so learning and transfer are inextricably linked.

Haskell explains that "The simple aspect of transfer of learning is exemplified whenever we say, for example, it's like... it's equivalent to... for example... it's akin to... for instance... it's the same as... by the same token... similarly... in the same way... it reminds me of... it resembles... it's comparable to... or, it's analogous to." [11]

Here are three instances of transfer in relation to a LEARNING (training) event:

  1. During the event, using learning that happened before the event.
  2. During the event, using learning that happened during the same event.
  3. After the event, using learning that happened during the event.

Clearly, transfer happens during and after learning events. The word TRANSFER in the equation is misleading because it only refers to the third possibility and implies that transfer is separate from learning.

3. Formal Learning is Insufficient

In my Ready-Set-Go-Show article I mentioned a research project that I had conducted with L&D professionals. I asked them to rate the level of development of the participants at the end of training events (courses). More than 95% of the respondents indicated that the participants were ‘not yet competent’.

Here are two comments that support this finding:

  • "When people learn to improve their job performance, they do not usually master the newly learned knowledge and skills. They need to practice and learn more in their job context to internalize what they have learned." [12]
  • "Most training programs are not going to lead to full competency at the end of training — full competency will only occur with practice and experience on the job." [13]

So why is it that so many training courses are unable to deliver the necessary level of competence at the end of the LEARNING? And I'm not talking about failure of the needs assessment or course design, although these can be contributing factors (especially insufficient practice).

Kevin Ford et al give an excellent example: "a salesperson might be trained on how to be assertive but not aggressive in conducting a sales meeting with a client. The situations, issues, and types of clients that can be simulated in the training program cannot match the range of situations or the diversity in clients faced on the job. Thus, key principles and skills from training must then be applied [practiced] by the trainee in the appropriate way with a diverse range of settings and people." [14]

The reason that formal LEARNING is frequently insufficient is that for many tasks, competence cannot be developed in isolation from real work. Even if the formal training provides appropriate realistic practice, competence development will probably require real-world practice (i.e. real-world learning experiences).

This essential practice can only take place via transfer of training/learning in the workplace, which means the learners have transitioned from formal learning to informal learning. As Jennifer Sparr et al tell us, "Transfer of training is a natural intersection between formal learning in training and informal learning at the workplace: Whereas concepts and explicit knowledge are taught in formal training, transfer of training happens in and through work practice." [15]

4. Transfer Involves Learning

Another issue with the Learning x Transfer Equation is related to my earlier point that it implies that learning and transfer are separate.

We have seen that definitions of TRANSFER give no indication that on-the-job application requires more learning, yet this is crucial to achieving competence and proficiency. In fact these definitions imply that all the necessary learning takes place during 'training' before it is 'transferred'. Contrast this with the statement that "The classical definition of successful transfer is that it is a product of the learning process where something learned in one context is used to assist learning in another context." [16]

That is exactly what needs to happen when formal learning is applied on-the-job. TRANSFER isn't an end in itself, but a stepping stone in a learning journey towards a desired level of performance. Returning to Hager and Hodkinson, they say "it is more realistic to view 'transfer' as renovation and expansion of previous knowledge via the experience of dealing with new situations in new settings." [9]

In a report concerning teachers' transfer of learning from training settings to classroom practice, Beverly Showers says, "the 'problem' of transfer is really a definition of a new stage of learning which becomes a problem only if it is not recognized." Furthermore, "Successful transfer requires a period of labor through which the skill is practiced in its context..." She goes on to say that "Even very experienced and capable teachers should be aware throughout the training process that they are going to have to gear themselves up for?a second stage of learning that will come after skill has been developed." [17]

The problem" of transfer is really a definition of a new stage of learning which becomes a problem only if it is not recognized.

"In essence, skills and knowledge created in the context of training should be put into practice and be developed further in the context of work." [8] There are two immediate implications that come to mind: (1) the workplace becomes a designated practice field, and (2) training programs include an on-the-job learning phase to ensure the necessary performance is achieved.

What This Means

The Learning x Transfer Equation indicates that "training" is about LEARNING and needs to be followed by TRANSFER, where the former is off-the-job (out of the flow of work) and the latter is on-the-job (in the flow of work). In particular, the equation implies that learning doesn’t involve transfer, and transfer doesn’t involve learning.

The problem with this equation is that it is wrong. As I’ve explained, you cannot have learning without transfer, and transfer at the workplace requires learning if the training is to produce competence/proficiency.

At the beginning of this article, I said that the Learning x Transfer Equation is not good enough. Actually, I am of the opinion that it is misleading and even detrimental to training. I think it sends the wrong messages and can negatively influence understanding, priorities, and responsibilities, and ultimately cause decisions and behaviour that undermines training effectiveness.

At the risk of sounding pretentious, I felt motivated to take Buckminster Fuller's advice [18]:

You never change things by fighting the existing reality. To change something, build a new model that makes the existing model obsolete.

I believe it’s time we replace the Learning x Transfer Equation with a formula that is more realistic and helpful. Hopefully I have provided a satisfactory justification.

Transformation of Learning

Change is inherent to TRANSFER. In the process of applying learning the learners may change their situation and change (adapt/adjust) their existing knowledge. According to Jeani Young, "When learners take what they gain from adult education programs and apply it—transfer it—to their own lives, there is change. This change occurs in individual learners, their context, and their learning." [19]

Earlier I referred to a research paper by Stephen Yelon which mentioned the law of exchange. In the paper the authors explain that, "when learners make applications, they affect objects, processes and people and, if aware, note and take away information about the results that they value." More specifically, "they may simply add their observation to a group of ideas or they may change elements in the constellation." Two of the subjects of the study referred to their thoughts "crystallizing". [10]

Carraher & Schliemann investigated the influence of prior knowledge and experience on learning about mathematical concepts. What they observed is that the students did "not simply unload a prior solution from their storehouse of knowledge." The students "crafted it on the spot, adjusting and adapting their prior knowledge in the process." They go on to say that, "It is precisely this active accommodation of knowledge to the demands of the situation (as understood by them) that so notably lacks in transfer accounts of learning." [7].

Learners are involved in a series of choices "to discard, maintain, apply, or modify trained knowledge and skills in their work context." [20] Research shows that "Proactive learners create transfer experiences in adapting and applying training content to the specific demands of their position and the dynamic environments in their organization." [15] Hence it is argued that "learning transfer is better viewed as a transition, an adaptive process, in which an individual plays an active role, applying and reshaping learning." [21]

In Beverly Showers' study of the transfer of teacher training, she states that, "once a teaching skill has been obtained it needs to be transformed during the process when it is transferred into the active repertoire." And, she clarifies this by saying that, "The conditions of the classroom are sufficiently different from training situations that one cannot simply walk from the training session into the classroom with the skill completely ready for use—it has to be changed to fit classroom conditions." [17]

A Professional Writing program placed senior undergraduate students as interns in a variety of organisations. A key question concerned the interns' application of learning and their achievements as novice writers. The researchers discovered that "what the interns experienced was not learning transfer, but rather a transformation of learning." To clarify, "As they took on and succeeded in, the writing tasks they had been assigned, the interns both enacted and further developed expert practices—with performance and learning happening at the same time." [22]

In an article concerning language learning, Diane Larsen-Freeman puts it this way, "transfer is not a matter of "exporting" an intact bit of knowledge from within the classroom to without, or even of students' "reusing" what they have been taught, but rather of students' transforming what they have learned." She explains that, "the transformation is partly due to the learners interacting with a different and changing context and partly due to internal reorganization of the learners' language resources." [23]

A New Equation

What I propose is an amended equation, also with two drivers:

  • I played with ideas like Initial Learning and Learning Foundation, finally settling on FORMATION, partly because I wanted to keep each driver to one word. The first driver forms the learning that is the foundation for the subsequent on-the-job learning required to develop competence and proficiency.
  • Choosing a name for the second driver was a no-brainer since it's clear that effective application of learning involves a transformation of what has been learned. So I went with TRANSFORMATION, which also results in the learner and performance being transformed.

No alt text provided for this image

This equation isn't as simple or as easy to remember as the original equation, but it is realistic. So what should it be called? The 'Formation x Transformation Equation' or the 'Form x Transform Equation'? Perhaps drop equation and simply refer to the two essential components: 'Form and Transform'. For now I think I'll revert back to the Training Effectiveness Equation. (Any suggestions will be appreciated.)

Since learning is fundamental to both drivers, we can hardly call ourselves learning professionals if we put all or most of our attention on the first driver. We need to ensure that our training programs encompass both drivers of effectiveness. We need to provide a suitable formation of off-the-job learning and then ensure it is transformed through on-the-job application.

Another Buckminster Fuller quote is particularly apt here. He said, "You can't change the way people think, all you can do is give them a tool, the use of which will change their thinking."?I’m optimistic that this equation will be effective in helping L&D people, managers and learners to think about training in a new way and achieve the performance benefits they expect.

Addendum (2024)

Since I wrote the above I have experimented with various descriptors of the "two core phases" (components) of effective training programs. I have found that the following equation seems to work best.

Although this version uses more words, I have found that it immediately makes sense to all stakeholders and naturally leads to the important discussion of why learning from application is so important and how to make sure it happens.

References

Page numbers of quotations included in this article are shown in [square brackets].

  1. Wikipedia. All Models are Wrong. https://en.wikipedia.org/wiki/All_models_are_wrong.
  2. Dana Gaines Robinson and James C. Robinson. Breaking Barriers to Skill Transfer. Training and Development Journal, January 1985, pp. 82-83 [82].
  3. Lara Barros Martins, Thaís Zerbini and Francisco J. Medina. Impact of Online Training on Behavioral Transfer and Job Performance in a Large Organization. Journal of Work and Organizational Psychology, Volume 35, Issue 1, 2019, pp. 27-37 [30].
  4. Ramnath Dixit and Vinita Sinha. Investigating Tools and Techniques to Promote Workplace Training Transfer. ?Journal of Workplace Learning, Volume ahead-of-print, Issue ahead-of-print, 2022, pp. 1-19 [1].?
  5. Ragini Chauhan, Piyali Ghosh, Alka Rai and Sanchita Kapoor. Improving Transfer of Training with Transfer Design: Does Supervisor Support Moderate the Relationship? Journal of Workplace Learning, Volume 29, Issue 4, 2017, pp. 268-285 [268].
  6. David N. Perkins and Gavriel Salomon. Knowledge to Go: A Motivational and Dispositional View of Transfer. Educational Psychologist, Volume 47, Issue 3, 2012, pp. 248-258 [249].
  7. David Carraher and Analúcia D. Schliemann. The Transfer Dilemma. The Journal of the Learning Sciences, Volume 11, Issue 1, 2002, pp. 1-24 [19].
  8. Rita Vermeulen and Wilfried Admiraal. Transfer as a Two-way Process: Testing a Model. Journal of European Industrial Training, Vol. 33, Issue 1, 2009, pp. 52-68 [53, 54].
  9. Paul Hager and Phil Hodkinson. Moving Beyond the Metaphor of Transfer of Learning. British Educational Research Journal, Volume 35, Issue 4, 2009, pp. 619-638 [622-623, 620].
  10. Stephen L. Yelon, Christopher B. Reznich and Deborah A. Sleight. Medical Fellows Tell Stories of Application: A Grounded Theory on the Dynamics of Transfer. Performance Improvement Quarterly, Volume 10, Issue 2, 1997, pp. 134-155 [152].
  11. Robert E. Haskell. Transfer of Learning: Cognition, Instruction, and Reasoning (Vol. A in the Educational Psychology Series). New York: Academic Press, 2001 [xiii, 10, 24].
  12. Rita C. M. Vermeulen. Narrowing the Transfer Gap; the Advantages of ''As If" Situations in Training. Journal of European Industrial Training, Volume 26, Issue 8, 2002, pp. 366-374 [369].
  13. Timothy T. Baldwin, J. Kevin Ford and Brian D. Blume. (2009) Transfer of Training 1988-2008: An Updated Review and Agenda for Future Research. In G. P. Hodgkinson and J. K. Ford (Eds.).?International Review of Industrial and Organizational Psychology, Volume 24, Chapter 2, pp. 41–70 [63]. Chichester, England: Wiley.
  14. J. Kevin Ford, Timothy T. Baldwin, and Joshua Prasad. (2018) Transfer of Training: The Known and the Unknown. Annual Review of Organizational Psychology and Organizational Behavior, Volume 5, 2018, pp. 201-225 [203].
  15. Jennifer L. Sparr, Kristin Knipfer, Friederike Willems. How Leaders Can Get the Most Out of Formal Training: The Significance of Feedback-Seeking and Reflection as Informal Learning Behaviors. Human Resource Development Quarterly, Vol. 28, No. 1, Spring 2017, pp. 29-54 [30].
  16. Howard E. Middleton and Liesbeth K. J. Baartman (Eds.) Transfer, Transitions and Transformations of Learning. International Technology Education Series (Vol. 11). Rotterdam: Sense Publishers. 2013 [2].
  17. Beverly Showers. Peer Coaching: A Strategy for Facilitating Transfer of Training. University of Oregon, Center for Educational Policy and Management. October 1984 [65-67].
  18. Edmund Jarratt Applewhite (Ed).?Synergetics Dictionary: The Mind of Buckminster Fuller; in Four Volumes. New York and London: Garland, 1986.
  19. Jeani C. Young. Understanding Transfer as Personal Change: Concerns, Intentions, and Resistance. New Directions for Adult and Continuing Education, Issue 137, Spring 2013, pp. 71-82 [72].
  20. Timothy T. Baldwin, J. Kevin Ford and Brian D. Blume. The State of Transfer of Training Research: Moving Toward More Consumer-Centric Inquiry. Human Resource Development Quarterly, Volume 28, Issue 1, Spring 2017, pp. 17-28 [24].
  21. Michelle Anderson and Adrian Beavis. Teaching for Learning Transfer: A Literature Review. The Victorian Curriculum and Assessment Authority (VCAA). 2020 [20]
  22. Graham Smart and Nicole Brown. Learning Transfer or Transforming Learning?: Student Interns Reinventing Expert Writing Practices in the Workplace. Technostyle, Volume 18, Issue 1, Fall 2002, pp. 117-141 [129].
  23. Diane Larsen-Freeman. Transfer of Learning Transformed. Language Learning, Volume 63, Issue s1, March 2013, pp. 107-129 [108, 119].

Author

Throughout my L&D career I have continuously researched and experimented with ways to increase learning effectiveness. Along the way I have immersed myself in the 'science of learning' and the 'science of instruction' and have learned from successes and failures.

I know from experience that training can be very powerful if appropriate and implemented properly, which means addressing both drivers in the revised Training Effectiveness Equation. I have personally been involved in designing and implementing training programs that consistently produced an ROI in excess of 100%.

Over the last 20+ years I have successfully delivered many professional development programs for learning specialists. I have also created and delivered programs to help managers get better results from employee development.

I offer blended online programs for maximising learner engagement and learner performance. These programs include a combination of virtual workshops and self-paced learning. They incorporate extensive research and the methods I personally use to design and deliver training that is engaging and effective.

My programs are based on the Predictable Performance Design Methodology and implemented in four phases according to the?Ready-Set-Go-Show Model. Thanks to the model, I won a Gold Award at LearnX in the category Best Learning Model: Custom/Bespoke. Check out my article:?Ready-Set-Go-Show Wins Gold.

If you would like to arrange a chat or want more info about my work, please email me at geoff@TrainingThatWorks.online.

David Jago

Project Facilitation Whizz | Helping You Maximise Project Engagement, Minimise Frustration and Build Workshop Expertise

2 å¹´

Many thanks for this Geoff. As ever, some powerful insights and takeaways! I really like your new formulation: Formation x Transformation = Results. As you would no doubt be aware, the same considerations apply to change efforts. I'm reminded of the graph that has trainer input/time/responsibility trending down over time and learner input/time/responsibility trending up over the same time frame. My formulation – inspired by yours and almost as elegant – is Catalysis x Proaction = Results.

赞
回复
Susanne Unger

From knowing to doing to performing: training & development programs designed to really work and impactful coaching for today’s learners.

2 å¹´

Thank you for this article, Geoff! Ramnath Dixit - well done, your work being included as "reference" :-)

Thanks for this article and explanation Geoff. It is certainly very insightful and I couldn't agree more on your analysis of the original equation. Also, the terminology of Form & Transform seems apt. I only query the "Results" part, or rather the use of an equation itself. By doing so, it feels like an end of the learning which seems, to me at least, far too transactional and short-serving. Happy to be disabused of my reservation with some further insight.

赞
回复
Deepika Batra

Learning & Performance Support Specialist | Artist | Writer

2 å¹´

Your article has given me some useful insights into the evaluation of learning project that I am working on. I learnt about the transformation of learning that happens beyond training. I think transfer of learning is a form of informal learning that should be captured and tracked the way we evaluate formal learning.

赞
回复
Taylor Blake

Degreed Experiments | Learning, Development, and Skills

2 å¹´

I like the new equation! The terminology feels like a better fit

要查看或添加评论,请登录

Geoff Rip的更多文章

  • Skills Training and the Work Environment

    Skills Training and the Work Environment

    How 'Transfer of Training Climate' and 'Continuous Learning Culture' impact training. Below is another research summary…

    3 条评论
  • Learning in the Flow of Work

    Learning in the Flow of Work

    What is your interpretation of this expression! What does it mean to your stakeholders? I first came across “learning…

    5 条评论
  • Eight Core Drives of Behaviour

    Eight Core Drives of Behaviour

    The DNA of Learning One of the most valuable principles I learned when I first got involved in training was to design…

    5 条评论
  • Transfer of Social and Emotional Learning

    Transfer of Social and Emotional Learning

    The third and final research summary from my consulting archives (for now). Below is a brief summary of the technical…

  • Contextual Factors Influence Training Effectiveness

    Contextual Factors Influence Training Effectiveness

    This is another research summary from my consulting archives. The title of the research paper is: The Influence of…

  • The Danger of a Negative Transfer of Learning Climate

    The Danger of a Negative Transfer of Learning Climate

    The following is my summary of a research paper entitled: Change, Transfer Climate and Customer Orientation: A…

  • Transfer of Training at Shell S.A.

    Transfer of Training at Shell S.A.

    Below is a copy of a 'working paper' that was published by the Graduate School of Business at the University of Cape…

    2 条评论
  • A Training Credibility Problem

    A Training Credibility Problem

    This is a real-life situation from my consulting archives. The Problem The general credibility of training at a new…

    2 条评论
  • Global Standard for L&D Metrics

    Global Standard for L&D Metrics

    I recently perused the first edition of ISO/TS 30437, entitled 'Human Resource Management - Learning and Development…

    8 条评论
  • Why NOT Use Learning Styles?

    Why NOT Use Learning Styles?

    Combatting the learning styles virus reminds me of the Whack-a-Mole arcade game. No matter how many times you whack…

    5 条评论

社区洞察

其他会员也浏览了