PSS: beyond the implementation gap

In the last couple of decades, a large number of papers on planning support systems (PSS) have been published in national and international, scientific and professional journals. What is remarkable about PSS is that for quite some time their history has been dominated by an implementation gap, that is, a discrepancy between supply and demand: despite the availability of a growing number and diversity of potentially valuable PSS instruments, planning practitioners are rather hesitant to buy, implement or apply them. This implementation gap leads to the question whether PSS are a valuable tool for planning practice. In this commentary, I answer this question by taking a closer look at the PSS debate from four perspectives, namely those of PSS history, PSS research, PSS education and PSS in practice. Although these perspectives are closely related, I show that they also reveal different aspects of this issue. For each of these perspectives, I start with a hypothetical conclusion and present some of my underlying considerations. At the end of this contribution, I summarize the situation, finalize the hypothetical conclusions and provide some recommendations concerning the implementation gap. These include focusing on the positive rather than the negative: we should look at the success stories (successful or best practices) and try to learn from them; after all, the proof of the pudding is in the eating. Furthermore, PSS are by no means a panacea for all our problems or challenges in planning practice. In my opinion, selectivity in their application in actual planning practice evidences a growing maturity of the PSS field