Are Hamas' Qassam rockets not very destructive?

Question

Recently there was this answer on Politics.SE, which quotes extensively from Norman Finkelstein's book, Gaza: An Inquest Into its Martyrdom. In particular, there was deep disagreement from this quote from Page 265

What’s yet more telling, it couldn’t account for the minimal Israeli property damage during Protective Edge. The Israel Ministry of Foreign Affairs website tracked on a daily basis the damage caused by Hamas rockets to civilian infrastructure. Table 5 summarizes its entries. The official Israeli postmortem on Protective Edge alleged that “several residential communities on the border with the Gaza Strip . . . were battered by rocket and mortar fire.” Yet, even allowing that a certain percentage landed in open areas, how could the thousands upon thousands of Hamas rockets have inflicted so little damage? How could only one Israeli house have been destroyed and 11 others hit or damaged by a mega barrage of rockets? The obvious and most plausible answer was that the preponderance of these so-called rockets amounted to enhanced fireworks or “bottle rockets.”

This seems to contradict other reports on the apparent destructive force of the rockets

A 5-year-old boy was killed and at least seven were injured Wednesday when a Hamas rocket slammed into an apartment building in an Israeli border town — as fighting between Palestinian militants and the Jewish State intensified.

There's a picture of a building on fire with a giant hole that appears to have been blown in the side (probably from the video in this tweet).

Are Hamas' Qassam rockets not very destructive or less destructive than expected?

Answer 1

Qassam rockets are essentially untargeted, flying improvised explosive devices (IEDs). As such, the objective is not to precisely hit a military target, but to strike terror in the civilian population (which it does successfully; for example, almost half of Sderot preteens show symptoms of PTSD).

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Finkelstein is underselling how inaccurate these rockets are, and is underestimating the effectiveness of Israels defenses (Iron Dome, warning systems, etc), in an attempt to downplay the potential destructiveness of individual rockets.

Of the 4500 rockets launched during Operation Protective Edge, 3600 fell in open spaces (and 200 exploded on launch or fell inside Gaza). 735 were intercepted by the Iron Dome. Only 225 of the 4500 (5%) fell in built-up areas. This resulted in "several dozen cases of damage to buildings", $20 million in direct damage to businesses, 2 deaths, and 69 people directly wounded (indicating a destructiveness well above bottle rockets).

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Looking beyond just the case of Protective Edge, rockets fired from 2005 to 2014 injured 2600 people and caused $160 million in property damage. Warhead weights range from 5 to 21kg (well above that of bottle rockets).

Answer 2

tldr: I think the question and tim's answer are both partly flawed. In this answer I attempt to explain why it's impossible to have an objective and reliable answer to this question.

The first problem is that the concept of "destructiveness" of a rocket is not objective. Clearly the rockets are lethal weapons, but quantifying their potential level of damage would require a baseline representing the normal level of destructiveness of a rocket in a similar context. This is impossible given that:

• Reliable information about the size of the arsenal and the type of rockets is very limited,
• There are serious biases to correctly estimating the impact of the rockets.

Type of rockets

Hamas and the other organizations use various types of rockets with different characteristics affecting their destructive power: components, weight, range, etc. For example "a few projectiles have contained white phosphorus said to be recycled from unexploded munitions used by Israel in bombing Gaza". It's also possible that some advanced rocket parts are smuggled into Gaza, potentially allowing some cases of very destructive rockets. On the other hand, the low level of technology of some of the rockets and/or of their firing mechanism is made clear by the fact that some rockets accidentally fall inside Gaza. Incidentally, this implies that the two observations made by OP do not necessarily contradict each other: it's possible that most of the rockets are poorly made and not very destructive while a few of them are advanced and very destructive.

Damage inflicted

It makes sense to quantify the destructiveness of the rockets by studying the damage that they inflict compared to how many are fired. The other answer follows this direction but fails to consider several problems:

• This Wikipedia page honestly cautions that "precisely counting the number of rockets fired is impossible, and differing estimates have been given. The injury figures and attack counts below are attributed to the Israeli Ministry of Foreign Affairs". Of course the Israeli government figures are the only ones available, but one can legitimately question whether their estimates are reliable. As explained in the PoliticsSE answer which is the source of the question, Israel has serious reasons to exaggerate the threat of Hamas rockets (see also below).
• The effectiveness of the Iron Dome and of other Israeli defense measures against Hamas rockets is an additional factor of uncertainty. Either these measures are very efficient, effectively preventing a lot of casualties despite the high destructiveness potential of the rockets; or they are only moderately effective, in which case the low/moderate level of casualties can be explained by the low destructiveness potential of the Hamas attacks (either because there are not that many rockets or they are not very destructive). Again there is very little objective evidence either way.

Unfortunately the only source of evidence for both the number of rocket attacks and their impact is the Israeli government. It's impossible to know whether the figures it provides are accurate due a clear conflict of interest: since Netanyahu took office in 2009, the Israeli government has maintained a tough line excluding any dialogue or compromise with Palestine as long as the threat of violence against Israeli citizens exists. Domestically and internationally, the current Israeli government relies on the seriousness of the threat to justify its policy. It's obvious to everyone that the threat exists, so the severity of the threat is the crucial point. This means that the government which claims that the threat is serious to justify its main policy is also the one which is in charge of assessing the seriousness of the threat. This cannot be dismissed as a negligible bias: the numbers might be perfectly accurate, but as long as they are not confirmed by some independent source it's reasonable to be skeptical about them.

The question looks like it should be possible to answer it objectively, but actually the honest answer is that there is not enough evidence to conclude, at least not enough evidence confirmed by several and/or neutral sources.

Answer 3

I spent some time creating some statistics so that one can judge for themselves how destructive Hamas's rocket barrages are.

Fatality rates

Statistics of the number of people killed in Israel by rockets fired from Gaza into Israel:

Period	Rockets	Killed	Ratio (in %)	Sources
20055	286	2	0.70	6 7 9 10
2006	974-1722	4	0.23-0.41	6 7 10 16
2007	783-1276	2	0.16-0.26	6 7 10 16
2008	1159-2048	5	0.24-0.43	6 7 10 16
2009	158-569	0	0.00	6 7 10 16
2010	103-150	1	0.67-0.97	6 7 10 16
2011	375-4194	2	0.48-0.53	8 10 16
2012	787-2221	3	0.14-0.38	10 12 16
2013	39-52	0	0.00	13 16
2014	4005-4225	63	0.14-0.15	14 15 16
2015	25	0	0.00	16
2016	15	0	0.00	16
2017	353	0	0.00	17
2018	3456	0	0.00	22
2019	1295	32	0.23	21
Sep 2005 - May 2007	2700	4	0.15	1
Nov 2018	400-500	21	0.40-0.50	2 4
May 2019	600-690	32	0.43-0.50	3 4
2018-2019	26003	5	0.19	4

Notes

1. A woman who was wounded by a rocket died months later, bringing the total to 2.
2. The fourth fatality was caused by an anti-tank missile and not a rocket.
3. Includes mortar shells.
4. According to Israeli sources, some 680 projectiles were launched from Gaza in 2011.
5. Does not include rockets launched at the then existing Israeli settlements in Gaza.
6. My estimate based counting attacks on List of Palestinian rocket attacks on Israel in 2018.

Caveats

• Journalists are awful at distinguishing mortars from rockets. They are completely different, carry more explosives, and cannot be intercepted by Israel's Iron Done missile defense system. Some of the fatalities in the above table may have been caused by mortar shells.
• Wikipedia has a bunch of pages listing rockets attacks per year, e.g List of Palestinian rocket attacks on Israel in 2020. Many of those pages include both anti-tank missiles, balloon-borne explosives, and mortars. All information on Wikipedia is supposed to be cited to "reliable sources" but that is not always the case.
• A fraction of the rockets fired does not penetrate Israel but land in Gaza. Such launches are included in some sources reporting but not in others.

This means that the above figures should be seen as estimates. Though if you find any errors in the data, please write so in the comments and I will update the data.

Since the Iron Dome came online in 2011, it makes sense to analyze the periods 2005-2010 and 2011-2019 separately to see if there are any statistically significant differences.

According to the statistics, between 2005 and 2010 between 3463 and 6051 rockets were fired into Israel, killing 14 people. The fatality rate was 0.23% and 0.39%. In other words, the Gaza militants required between 256 and 435 to kill a single person. Between 2011 and 2019 between 6921 and 8632 rockets were fired into Israel, killing 14 people. The fatality rate was between 0.16% and 0.21%. Thus, it took the militants between 494 and 617 rockets to kill a single person.

Therefore, it appears that the Iron Dome has made it somewhat harder for the Gaza militants to kill Israelis. Although we cannot discount other potential factors, such as worse rockets, and improved Israeli early warning systems and air raid shelters.

Interception rates

We can also look at statistics for how often the Iron Dome successfully intercepts a rocket:

Period	Fired	Intercepted	Ratio (in %)	Souces
Nov 2012	1456	409	28%	11
Jul 14, 20181	174	over 30	over 17%	20
Aug 8, 2018	8	2	25%	19
Nov 11, 2018	17	3	18%	18
May 20191	690	240	35%	4
2019	1295	478	37%	21

Notes

1. Includes mortars.

Fishy statistics

The Israeli Defence Force (IDF) claims that the Iron Dome's interception rate exceeds 85%. In a recent tweet, it claimed that Hamas fired about 4 360 rockets "at" Israel and that 90% were intercepted by the Iron Dome, and those that weren't killed 11 Israelis. This claim is hard to reconcile with the above statistics.

One article claims, like the IDF's tweet implies, that "the vast majority of the rockets recently fired by Hamas were intercepted", another that only 1 500 of Hamas's rockets were headed towards built-up areas and of those 90% were intercepted.

It's reasonable to assume that virtually all Israeli casualties are in built-up areas. Therefore, if the Iron Dome hadn't existed, ten times as may Israelis, 110, would had died in the recent conflict. So one Israeli killed for every 40 rockets fired (4360 / 110). Why did it previously take Hamas hundreds of rockets to kill a single Israeli but now 40 would have been sufficient without the Iron Dome?

These numbers are hard to reconcile with the above statistics. If it is true that the Iron Dome prevents 90% of all potential Israeli fatalities then it must also be true that Hamas has massively improved its rocket technology. Indeed, Michael J. Armstrong argues that Hamas has improved its rocketry:

Accuracy has improved, too. About 50 per cent of the rockets arriving over Israel have threatened populated areas. That’s up from 22 per cent in 2012 and 18 per cent in 2014. Fewer rockets land in empty fields after missing their targets.

Gaza’s enhanced rocket technology challenges Israel’s defences

I cannot find any sources for his numbers.