IISS

IISS became central to the Iran conflict through its Arrow-3 depletion analysis and its Military Balance data on Iranian missile stocks. Its assessment that Arrow-3 stocks were 81.33% depleted by 26 March 2026 was the most cited independent estimate of Israel's air-defence crisis. By Day 60, with the conflict in a diplomatic holding pattern around the 1 May WPR clock and OFAC GL-V's 24 May Deadline, IISS analysis has shifted to the longer-term question of what a sustained Hormuz disruption does to regional military balance and whether Iran's nuclear sequencing mirrors the North Korea precedent.

The International Institute for Strategic Studies (IISS) is a London-based independent research institute founded in 1958. It employs roughly 350 staff across offices in London, Washington DC, Manama, Singapore, and Berlin. Director-General since 2022 is Bastian Giegerich, a former Bundeswehr officer and strategic-studies academic. IISS is best known for its annual Military Balance, the globally referenced dataset on armed forces, defence budgets, and equipment inventories for over 170 countries. It also publishes Strategic Survey (annual geopolitical assessment), Adelphi Papers (long-form monographs), and the peer-reviewed Survival journal.

IISS occupies a specific niche in the London think-tank ecosystem alongside RUSI and Chatham House: it is primarily a quantitative and strategic-studies institution rather than a policy-advocacy body. Its Military Balance methodology documents force structures with line-item granularity -- aircraft hull counts, missile inventories, submarine classes -- making it the default citation for parliamentary testimony, NATO planning documents, procurement hearings, and financial risk analysis on commodity and sovereign-bond desks. When governments or news organisations need an unclassified figure for how many F-35s Israel has or what the Russian tank fleet looked like before the Ukraine invasion, The Military Balance is the standard reference.

IISS also holds substantial convening power through two flagship annual events: the Shangri-La Dialogue in Singapore (the principal Track 1.5 security forum for the Asia-Pacific) and the Manama Dialogue in Bahrain (the Gulf security counterpart). Defence ministers, service chiefs, and intelligence officials attend as a signal of engagement with the Western security framework. The combination of data authority and convening power makes IISS an institution that shapes the agenda for defence debates rather than merely commenting on them.

Across Lowdown's topics, IISS has provided the evidentiary baseline for analysis of Russian force reconstitution timelines, Arrow-3 missile-stock depletion during the Iran conflict, drone industrial capacity in Ukraine, and naval balance shifts in the Indo-Pacific. Its methodology sets the standard against which other think-tank assessments are cross-checked when they diverge.

IISS has been a consistent methodological anchor in Lowdown's Russia-Ukraine coverage. Its Military Balance data underpins estimates of Russian force reconstitution timelines, providing the baseline equipment figures against which Ukrainian General Staff and Western intelligence assessments are cross-checked. When Lowdown reported on the 16-year low in Russian refinery output and the shift in drone campaign posture , IISS industrial-capacity benchmarks supplied the reference frame. IISS analysis also informed the assessment of Russian casualty rates, cited in coverage of declining engagement rates despite elevated attrition . The institute has not published a dedicated Ukraine Ceasefire assessment, but its force-reconstitution modelling is the primary Western open-source basis for how long Russia can sustain high-tempo operations without strategic pause.