There are two limitations that need further consideration

The gap

Evidence profile

Stated in the limitations and future work sections of the source papers, classified as general, drawn from work published between 1980 and 2026, spanning 2 journals.

Supporting evidence — 3 representative gaps

• The effect of blended learning approaches on vocational school students’ practical skills performance and learning behaviors: virtual simulations or hands-on activities while accessing instructional videos (2026) · Instructional Science · doi

  There are two limitations that need further consideration. First, the instructional content focused solely on the basic skill of circuit fault detection, whereas practical workplace skills typically involve three-dimensional spatial operations and dynamic tool interactions, such as welding, automotive repair, and animation production. Although videos demonstrated generalized ability in basic tasks, their efficacy in enhancing spatial visualization and motor coordination remains unverified. Spatial ability is a critical predictor of three-dimensional skill acquisition, which necessitates video designs that integrate perspective shifts and dynamic decomposition (Höffler & Leutner, 2007). Future studies should extend to domains The effect of blended learning approaches on vocational school…1 3 39 Page 18 of 23 like mechanical assembly or surgical simulation to validate generalized ability. Second, the 45-minute short-term intervention captured immediate learning effects but could not assess long-term retention or transfer ability. Skill consolidation requires repetitive practice and spaced reinforcement (Sitzmann & Ely, 2011). Brief exposure to learning approaches and video review may be insufficient to support sustained learning. To address these issues, sub- sequent research could enhance the complexity of testing materials and compare learning outcomes across different task types. Additionally, incorporating delayed post-tests would help verify the effects of various learning approaches and video-based instruction on stu- dents’ skill internalization and retention.

  generalstated in limitationsevidence 5/5
  Keywords: learning skill ability spatial video approaches basic three dimensional dynamic generalized term effects retention there
• Conceptual and procedural knowledge retention in data visualization: a longitudinal study of doctoral learning and instructional design implications (2026) · Instructional Science · doi

  Several limitations should be acknowledged. An important limitation concerns the instruc- tional design of the intervention itself. The training examined in this study consisted of an intensive initial instructional phase, but it did not include structured reinforcement through 1 3F. J. Jiménez-Hornero, E. G. de RavéPage 23 of 29 51 spaced retrieval, low-stakes testing, or repeated guided application after the course ended. From this perspective, the observed decline in performance, especially in procedural, tool- dependent skills, is not unexpected and should not be interpreted as evidence that visu- alization learning is inherently unstable. Rather, it suggests that a one-time instructional intervention is insufficient for long-term retention of complex data-visualization compe- tence. Research on retrieval practice and test-enhanced learning has shown that repeated recall opportunities, distributed over time and supported by feedback, can improve long- term retention and application of knowledge (Schwieren et al., 2017; Larsen et al., 2013). Future studies should therefore compare the present course-based model with evidence- informed alternatives that incorporate spaced practice, retrieval-based exercises, cumulative low-stakes quizzes, or follow-up graphing tasks embedded across the doctoral trajectory. Another important limitation is that the study did not directly document the learning experiences in which participants engaged between the three assessment points. Although the doctoral context is relevant for interpreting the transition from formal instruction to more independent research activity, the present design did not examine which features of the doctoral program, supervisory practices, research tasks, or informal learning opportuni- ties may have shaped retention outcomes. As a result, the study cannot determine which specific programmatic conditions supported or hindered the maintenance of data-visualiza- tion competence over time. Future research should therefore investigate these intervening experiences more directly, for example through longitudinal tracking of research activity, supervisory feedback, methodological use in ongoing projects, and students’ self-reported opportunities for continued practice. The study was conducted in a single institutional context with a modest sample size, which may limit the generalizability of results. Although linear mixed-effects modeling effectively addressed within-subject dependency and missing data, subsequent work should include larger, more diverse samples and possibly nonlinear modeling to explore alternative trajectories of change. The one-year observation period also captures only an initial phase of skill retention. Longitudinal studies extending over multiple years could determine whether procedural decline stabilizes, reverses, or continues as doctoral students advance toward dissertation work. Moreover, future research should investigate the mechanisms underlying retention and loss. Qualitative approaches, such as reflective journals, interviews, or think-aloud proto- cols, could complement quantitative models to illuminate how doctoral students perceive the relevance and use of data visualization in their ongoing research practice. Examining environmental factors such as access to visualization software, supervisory support, and par- ticipation in research communities of practice would help explain the contextual influences shaping skill maintenance. As Sinclair et al. (2013) note, doctoral learning environments are powerful mediators of skill development, and institutional culture often determines whether early gains are sustained or dissipated over time.

  generalstated in limitationsevidence 5/5
  Keywords: doctoral learning retention practice time retrieval visualization future supervisory students skill important limitation design intervention
• Cognitive monitoring: From learning theory to instructional applications (1980) · ECTJ · doi

  The cognitive monitoring approach pre- sents a comprehensive view of the learning process. For this reason it can be used to derive possible instructional manipula- tions, classify previously conducted re- search, and identify knowledge gaps that future research could fill. Considering what has been stated here thus far, the most obvious future research should be the comprehensive application of cognitive operation monitoring strate- gies to instructional texts. Specific treat- ments (e.g., embedded questions and ob- jectives) have been used to increase learn- ing and retention, but the incorporation of strategies to monitor each cognitive opera- tion has not been attempted. It would seem most advantageous to take a comprehen- sive approach with experienced and eld- erly learners. These populations have the metacognitive knowledge and monitoring capacity necessary for the initial experi- ments. It would be important to consider the type of format (primary or secondary) and the type of learning outcome when conducting these studies. It may be found that the comprehensive approach requires too much student time or effort for completion. Another approach would be to combine two or three opera- tion monitoring strategies within the text. A number of experiments could be devised to compare various groupings of operation monitoring strategies, with time and learn- ing acheivement being the dependent vari- ables. These experiments could be con- ducted at each of the developmental levels. The importance placed on student- generated encodings should receive more empirical validation. Experiments with text could be designed to compare retention by a picture-viewing group and by a picture- generating group. For young learners this experiment could be modified to include a picture-viewing group and a picture- completing group that draws the remain- der of a partially presented picture. Similar activities could be designed for verbal stimuli. For the control groups a highlight- ed main idea statement could be placed in the text or the column next to it. The exper- imental group could generate the main idea statement or complete a partially pre- sented one. Another useful experiment re- lated to learner-generated encoding would be picture-presented, imagery-directed, picture-generated, and high-imagery text. The generation hypo- thesis would favor the picture-generated treatment because of its overt responding requirement. compare to The qualitative encoding notion seems to be particularly powerful. Since it empha- sizes original rather than correct responses, and since all learners have some original- ity, it would appear worthwhile to pursue this topic at each developmental level and particularly w

  generalstated in future workevidence 5/5
  Keywords: picture monitoring group approach text generated cognitive comprehensive strategies learners experiments compare learning used instructional

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