So, why would CMLCA claim to be scientific software? Of course this is subjective and debatable, but there are good arguments:
It is probably the only software for LCA that has been developed entirely at a university.
It has been designed with university students, PhD students and academic staff as the primary audience, whereas most LCA programs have a prime focus on consultants.
The internal machinery has been described in the scientific literature, to a far better extent than that of other LCA programs.
Concerning this last point, important aspects has been published in the following books:
R. Heijungs. Probability, statistics, and life cycle assessment. Guidance for dealing with uncertainty and sensitivity. Springer (ISBN 978-3-031-49316-4), Cham, 2024.
R. Heijungs & S. Suh. The computational structure of life cycle assessment. Kluwer Academic Publishers (ISBN 1-4020-0672-1), Dordrecht, 2002, xii+241 pp.
R. Heijungs. A theory of the environment and economic systems. A unified framework for ecological economics and decision-support. Edward Elgar (ISBN 1-84064-643-8), Cheltenham, 2001, 341 pp.
and in the following journal articles:
R. Heijungs. Analysis and remediation of the confusing specification of the lognormal distribution. International Journal of Life Cycle Assessment 29:3 (2024), 537-554.
R. Heijungs, Y. Yang & H.-S. Park. A or I-A? Unifying the computational structures of process- and IO-based LCA for clarity and consistency. Journal of Industrial Ecology 26:5 (2022), 1824-1836.
M.A. Mendoza Beltrán, R. Heijungs, J.B. Guinée & A. Tukker. A pseudo-statistical approach to treat choice uncertainty. The example of partitioning allocation methods. International Journal of Life Cycle Assessment 21:2 (2016), 252-264.
R. Heijungs. Topological network theory and its application to LCA and related industrial ecology tools. Journal of Environmental Accounting and Management 3:2 (2015), 151-167.
R. Heijungs, A. de Koning & A. Wegener Sleeswijk. Sustainability analysis and systems of linear equations in the era of data abundance. Journal of Environmental Accounting and Management 3:2 (2015), 109-122.
E.A. Groen, R. Heijungs, E.A.M. Bokkers & I.J.M. de Boer. Methods for uncertainty propagation in life cycle assessment. Environmental Modelling & Software 62 (2014), 316-325.
R. Heijungs & M. Lenzen. Error propagation methods for LCA. A comparison. International Journal of Life Cycle Assessment 19:7 (2014), 1445-1461.
R. Heijungs, E. Settanni & J. Guinée. Toward a computational structure for life cycle sustainability analysis: unifying LCA and LCC. International Journal of Life Cycle Assessment 18:9 (2013), 1722-1733.
R. Heijungs. Sensitivity coefficients for matrix-based LCA. International Journal of Life Cycle Assessment 15:5 (2010), 511-520.
S. Suh & R. Heijungs. Power series expansion and structural analysis for life cycle assessment. International Journal of Life Cycle Assessment 12:6 (2007), 381-390.
R. Heijungs, J.B. Guinée, R. Kleijn & V. Rovers. Bias in normalization: causes, consequences, detection and remedies. International Journal of Life Cycle Assessment 12:4 (2007), 211-216.
R. Heijungs & J.B. Guinée. Allocation and "what-if" scenarios in life cycle assessment of waste management systems. Waste Management 27:8 (2007), 997-1005.
R. Heijungs, A. de Koning, S. Suh & G. Huppes. Toward an information tool for integrated product policy. Requirements for data and computation. Journal of Industrial Ecology 10:3 (2006), 147-158.
R. Heijungs & S. Suh. Reformulation of matrix-based LCI: from product balance to process balance. Journal of Cleaner Production 14:1 (2006), 47-51.
R. Heijungs, S. Suh & R. Kleijn. Numerical approaches to life cycle interpretation. The case of the Ecoinvent'96 database. International Journal of Life Cycle Assessment 10:2 (2005), 103-112.
R. Heijungs & R. Frischknecht. Representing statistical distributions for uncertain parameters in LCA. Relationships between mathematical forms, their representation in EcoSpold, and their representation in CMLCA. International Journal of Life Cycle Assessment 10:4 (2005), 248-254.
J.B. Guinée, R. Heijungs & G. Huppes. Economic allocation: examples and derived decision tree. International Journal of Life Cycle Assessment 9:1 (2004), 23-33.
R. Heijungs & R. Kleijn. Numerical approaches to life-cycle interpretation. Five examples. International Journal of Life Cycle Assessment 6:3 (2001), 141-148.
R. Heijungs & R. Frischknecht. A special view on the nature of the allocation problem. International Journal of Life Cycle Assessment 3:6 (1998), 321-332.
R. Heijungs. Identification of key issues for further investigation in improving the reliability of life-cycle assessments. Journal of Cleaner Production 4:3/4 (1996), 159-166.
R. Heijungs. A generic method for the identification of options for cleaner products. Ecological Economics 10:1 (1994), 69-81.
R. Heijungs & J.B. Guinée. Software as a bridge between theory and practice in life cycle assessment. Journal of Cleaner Production 1:3/4 (1993), 185-189.